MAGIC
   
Selected Journal Publications
   

       

  • Stromer, J., Ladani, L., 2018. Influence of microstructure on the high-frequency ultrasound measurement of peak density ASME. ASME J Nondestructive Evaluation.():. doi:10.1115/1.4041067. Link

  • Keshawarz, A., Sadowski, M., Ladani, L., 2018. Direct Metal Laser Melting of Inconel 718: Process Impact on Grain Formation and Orientation Journal of Alloys and Compounds, Volume 736, 5 March 2018, Pages 297-305 Link

  • Stromer, J., Ladani, L., 2018. Examination of a spectral-based ultrasonic analysis method for materials characterization and evaluation Biomedical Signal Processing and Control, Volume 40, February 2018, Pages 454-461 Link

  • Ladani, L., Andreotta, R., & Brindley, W. (2017). Finite element simulation of laser additive melting and solidification of Inconel 718 with experimentally tested thermal properties. Finite Elements in Analysis and Design, 135, 36–43. Link

  • Ladani, L., Awad, I., She, Y., Dardona, S. and Schmidt, W., 2017. Fabrication of Carbon Nanotube/Copper and Carbon Nanofiber/Copper Composites for Microelectronics. Materials Today Communications, Volume 11, June 2017, Pages 123–131 Link

  • Ladani, L., Romano, J., Brindley, W. and Burlatsky, S., 2016. Effective Liquid Conductivity for Improved Simulation of Thermal Transport in Laser Beam Melting Powder Bed Technology. Additive Manufacturing. Link

  • Choudhury, S.F. and Ladani, L., 2016. Miniaturization of micro-solder bumps and effect of IMC on stress distribution. Journal of Electronic Materials, 45(7), pp.3683-3694. Link

  • Choudhury, S.F. and Ladani, L., 2016. Local shear stress-strain response of Sn-3.5 Ag/Cu solder joint with high fraction of intermetallic compounds: Experimental analysis. Journal of Alloys and Compounds, 680,pp.665-676. Link

  • Sadowski, M., Ladani, L., Brindley, W. and Romano, J., 2016. Optimizing quality of additively manufactured Inconel 718 using powder bed laser melting process. Additive Manufacturing, 11, pp.60-70. Link

  • Ladani, L., 2016. Erratum to: Local and Global Mechanical Behavior and Microstructure of Ti6Al4V Parts Built Using Electron Beam Melting Technology. Metallurgical and Materials Transactions A, 5(47), pp.2537-2537. Link

  • Romano, J., Ladani, L., Razmi, J. and Sadowski, M., 2015. Temperature distribution and melt geometry in laser and electron-beam melting processes–A comparison among common materials. Additive Manufacturing, 8, pp.1-11. Link

  • Choudhury, S.F. and Ladani, L., 2015. Effect of intermetallic compounds on the thermomechanical fatigue life of three-dimensional integrated circuit package microsolder bumps: finite element analysis and study. Journal of Electronic Packaging, 137(4), p.041003. Link

  • Ladani, L. and Abdelhadi, O., 2015. Structural Size Effect on Mechanical Behavior of Intermetallic Material in Solder Joints: Experimental Investigation. Journal of Electronic Packaging, 137(1), p.014501. Link

  • Magee, A.C. and Ladani, L., 2015. Representation of a microstructure with bimodal grain size distribution through crystal plasticity and cohesive interface modeling. Mechanics of Materials, 82, pp.1-12. Link

  • Ladani, L., 2015. Local and Global Mechanical Behavior and Microstructure of Ti6Al4V Parts Built Using Electron Beam Melting Technology. Metallurgical and Materials Transactions A, 46(9), pp.3835-3841. Link

  • Awad, I. and Ladani, L., 2015. Mechanical integrity of a carbon nanotube/copper-based through-silicon via for 3D integrated circuits: a multi-scale modeling approach. Nanotechnology, 26(48), p.485705. Link

  • Choudhury, S.F. and Ladani, L., 2015. Single crystal plasticity finite element analysis of Cu6Sn5 intermetallic. Metallurgical and Materials Transactions A, 46(3), pp.1108-1118. Link

  • Ladani, L., 2015. Copper-CNT Hybrid TSVs: Thermo-Mechanical Stresses and Reliability Analysis. International Journal of High Speed Electronics and Systems, 24(03n04), p.1550006. Link

  • Romano, J., Ladani, L.and Sadowski, M., 2015. Thermal modeling of laser based additive manufacturing processes within common materials. Procedia Manufacturing, 1(03n04), pp.238-250. Link

  • Ladani, L., Razmi, J. and Choudhury, S.F., 2014. Mechanical Anisotropy and Strain Rate Dependency Behavior of Ti6Al4V Produced Using E-Beam Additive Fabrication. Journal of Engineering Materials and Technology, 136(3), p.031006. Link

  • Choudhury, S.F. and Ladani, L., 2014. Grain growth orientation and anisotropy in Cu6Sn5 intermetallic: nanoindentation and electron backscatter diffraction analysis. Journal of electronic materials, 43(4), pp.996-1004. Link

  • Awad, I. and Ladani, L., 2014. Cohesive zone model for the interface of multiwalled carbon nanotubes and copper: molecular dynamics simulation. Journal of Nanotechnology in Engineering and Medicine, 5(3), p.031007. Link

  • Razmi, J., Ladani, L., and Aggour, S.M., 2014. Finite element simulation of pile behaviour under thermo-mechanical loading in integral abutment bridges. Structure and Infrastructure Engineering, 10(5), pp.643-653. Link

  • Abdelhadi, O.M. and Ladani, L., 2013. Effect of joint size on microstructure and growth kinetics of intermetallic compounds in solid-liquid interdiffusion Sn3. 5Ag/Cu-substrate solder joints. Journal of Electronic Packaging, 135(2), p.021004. Link

  • Magee, A.C. and Ladani, L., 2013. Temperature dependency of mechanical behavior and strain rate sensitivity of an Al–Mg alloy with bimodal grain size. Materials Science and Engineering: A, 582, pp.276-283. Link

  • Razmi, J., Ladani, L., and Aggour, M.S., 2013. Fatigue crack initiation and propagation in piles of integral abutment bridges. Computer‐Aided Civil and Infrastructure Engineering, 28(5), pp.389-402. Link

  • Awad, I. and Ladani, L., 2013. Interfacial strength between single wall carbon nanotubes and copper material: molecular dynamics simulation. Journal of Nanotechnology in Engineering and Medicine, 4(4), p.041001. Link

  • Abdelhadi, O.M., Magee, A.C., and Ladani, L., 2013. Optimization of Preparation Process for Successful Electron Backscatter Diffraction of Multilayer Specimens: Application to Lead-Free Solder Joints. Journal of Advanced Microscopy Research, 8(1), pp.10-20. Link

  • Abdelhadi, O. and Ladani, L., 2013. Effect of joint size on microstructure and growth kinetics of intermetallic compounds in solid-liquid interdiffusion Sn3.5Ag/Cu-substrate solder joints. ASME Journal of Electronic Packaging, 135(2), p.021004. Link

  • Magee, A.C. and Ladani, L.J., 2013. Temperature Effects in Al 5083 with a Bimodal Grain Size. In MRS Proceedings (Vol. 1513, pp. mrsf12-1513). Cambridge University Press. Link

  • Magee, A. and Ladani, L., 2013. Strength and Failure of Ultrafine Grain and Bimodal Al‐Mg Alloy at High Temperatures. Light Metals 2013, pp.277-282. Link

  • Abdelhadi, O.M. and Ladani, L., 2012. IMC growth of Sn-3.5 Ag/Cu system: combined chemical reaction and diffusion mechanisms. Journal of Alloys and Compounds, 537, pp.87-99. Link

  • Magee, A., Ladani, L., Topping, T.D. and Lavernia, E.J., 2012. Effects of tensile test parameters on the mechanical properties of a bimodal Al–Mg alloy. Acta Materialia, 60(16), pp.5838-5849. Link

  • Harvey, E., Ladani, L. and Weaver, M., 2012. Complete mechanical characterization of nanocrystalline Al–Mg alloy using nanoindentation. Mechanics of Materials, 52, pp.1-11. Link

  • Ladani, L. and Razmi, J., 2012. Mechanical strength and failure characterization of sn-ag-cu intermetallic compound joints at the microscale. Journal of electronic materials, 41(3), pp.573-579. Link

  • Razmi, J., Ladani, L. and Aggour, M.S., 2012. Fatigue life of piles in integral-abutment bridges: Case study. Journal of Bridge Engineering, 18(10), pp.1105-1117. Link

  • Nelson, S., Ladani, L., Topping, T. and Lavernia, E., 2011. Fatigue and monotonic loading crack nucleation and propagation in bimodal grain size aluminum alloy. Acta Materialia, 59(9), pp.3550-3570. Link

  • Abdelhadi, O.M., Ladani, L. and Razmi, J., 2011. Fracture toughness of bonds using interfacial stresses in four-point bending test. Mechanics of Materials, 43(12), pp.885-900. Link

  • Gyllenskog, J. and Ladani, L., 2011. Fatigue crack initiation and propagation in aileron lever using successive-initiation modeling approach. Journal of Aircraft, 48(4), pp.1387-1395. Link

  • Ladani, L. and Nelson, S., 2011. Transition of crack propagation path under varied levels of load in bimodal grain size Al-Mg alloy. Journal of Engineering Materials and Technology, 133(4), p.041017. Link

  • Ladani, L.J., 2010. Numerical analysis of thermo-mechanical reliability of through silicon vias (TSVs) and solder interconnects in 3-dimensional integrated circuits. Microelectronic Engineering, 87(2), pp.208-215. Link

  • Ladani, L.J., 2010. Stress analysis of 3-dimensional IC package as function of structural design parameters. Microelectronic Engineering, 87(10), pp.1852-1860. Link

  • Ladani, L.J., 2010. Successive softening and cyclic damage in viscoplastic material. Journal of Electronic Packaging, 132(4), p.041011. Link

  • Ladani, L.J., Razmi, J. and Bentley, J., 2010. Microstructure and mechanical strength of snag-based solid liquid inter-diffusion bonds for 3 dimensional integrated circuits. Thin Solid Films, 518(17), pp.4948-4954. Link

  • Ladani, L.J. and Razmi, J., 2010. Probabilistic design approach for cyclic fatigue life prediction of microelectronic interconnects. IEEE Transactions on Advanced Packaging, 33(2), pp.559-568. Link

  • Ladani, L.J. and Nelson, S., 2010. A novel piezo-actuator-sensor micromachine for mechanical characterization of micro-specimens. Micromachines, 1(3), pp.129-152. Link

  • Ladani, L.J., 2010. Failure site transition in Pb-free solder joints caused by manufacturing variabilities in BGA and MLF components in low cycle fatigue analysis. International Journal of Materials and Product Technology, 37(3-4), pp.312-327. Link

  • Ladani, L.J. and Dasgupta, A., 2009. A meso-scale damage evolution model for cyclic fatigue of viscoplastic materials. International Journal of Fatigue, 31(4), pp.703-711. Link

  • Ladani, L.J. and Razmi, J., 2009. An anisotropic mechanical fatigue damage evolution model for Pb-free solder materials. Mechanics of Materials, 41(7), pp.878-885. Link

  • Ladani, L.J. and Dasgupta, A., 2008. Damage initiation and propagation in voided joints: modeling and experiment. Journal of electronic packaging, 130(1), p.011008. Link

  • Ladani, L.J., Dasgupta, A., Cardoso, I. and Monlevade, E., 2008. Effect of selected process parameters on durability and defects in surface-mount assemblies for portable electronics. IEEE Transactions on Electronics Packaging Manufacturing, 31(1), pp.51-60. Link

  • Ladani, L.J., 2008. Reliability estimation for large-area solder joints using explicit modeling of damage. IEEE Transactions on Device and Materials Reliability, 8(2), pp.375-386. Link

  • Ladani, L.J., 2008. Estimating fatigue damage model constants with maximum likelihood method. International Journal of Materials and Structural Integrity, 2(1-2), pp.164-172. Link

  • Ladani, L.J. and Dasgupta, A., 2007. Effect of voids on thermomechanical durability of Pb-free BGA solder joints: Modeling and simulation. Journal of electronic packaging, 129(3), pp.273-277. Link

  • Ladani, L.J., Das, D., Cartwright, J.L., Yenkner, R. and Razmi, J., 2006. Implementation of Six Sigma quality system in Celestica with practical examples. International Journal of Six Sigma and Competitive Advantage, 2(1), pp.69-88. Link

     
    Patents
   

       

  • Doyle, T.E., Thompson, L.A. and Ladani, L.J., 2014. Instant, in-situ, nondestructive material differentiation apparatus and method. U.S. Patent Application 14/264,233. Link

           

  • Ladani, L.J., Razmi, J. and Carter, J.M., Utah State University, 2012. Mechanical test fixture with submicron tolerance. U.S. Patent 8,096,191. Link

           

  • Ladani, L., Utah State University, 2012. Mechanical properties testing device and method. U.S. Patent 8,132,466. Link

     
    Selected Conference Publications
   

       

           

  • Magee, A., and Ladani, L.. Microscale deformation of an Al-Mg alloy with bimodal grain size investigated through crystal plasticity and grain boundary modeling. 2015 TMS Annual Meeting & Exhibition, MARCH 15-19, 2015. Orlando, FL, USA.

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  •  Ladani, L., “Local and Global Mechanical Behavior and Microstructure of Ti6Al4V Parts Built Using Electron Beam Melting Technology,” 2015 TMS Annual Meeting & Exhibition, MARCH 15-19, 2015. Orlando, FL, USA

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  • Choudhury, S., and Ladani, L., “Slip Parameters for Crystal Plasticity Finite Element Analysis of Cu6Sn5 Single Crystal Intermetallic in Solder Joint: Experiment, Modeling and a Comparative Analysis,” 2015 TMS Annual Meeting & Exhibition, MARCH 15-19, 2015. Orlando, FL, USA.

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  • Awad, I., and Ladani, L., Molecular Dynamics Study of the Temperature effect on Cohesive Zone Properties of Multi-Walled Carbon Nanotubes/Copper Interface,” 2015 TMS Annual Meeting & Exhibition, MARCH 15-19, 2015 • Orlando, FL, USA.

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  • Ladani, L., “Through Silicon Vias: Reliability and Integration of New Materials,” Connecticut Microelectronics and Optoelectronics Symposium Program Wednesday April 9, 2014, Short paper.

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  • Choudhury, S., Ladani, L., “Anisotropic Behavior of Single Grain Cu6Sn5 Intermetallic,” ASME IMECE 2014, Nov. 14-18, Montreal Canada.

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  • Awad, I., Ladani, L., “Molecular Dynamics Simulation of the Interfacial Strength between Single Wall Carbon Nanotubes and Copper in Through Silicon Vias,” ASME IMECE 2014, Nov. 14-18, Montreal Canada.

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  • Roy, L., and Ladani, L., “Mechanical Behavior of Ti-6Al-4V Manufactured by Electron Beam Additive Fabrication,” ASME 2013, Manufacturing Science and Engineering Conference, June 10-14, Madison, WI.

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  • Choudhury, S.F., and Ladani, L., “Experimental observation of the effect of crystallographic orientation on mechanical behavior of single crystal Cu6Sn5 intermetallics,” ASME International Technical Conference and Exhibition  on Packaging and Integration of Electronic and Photonic Microsystems (InterPACK 2013), July 16–18, 2013, Burlingame, California.

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  • Razmi, J., Aggour, M.S., and Ladani, L., “Analytical determination of pile failure due to fatigue,” 7th New York City Bridge Conference, August 26-27, 2013, New York City, NY.

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  • Magee, A. C., and Ladani, L.J. "Temperature Effects in Al 5083 with a Bimodal Grain Size." MRS Proceedings. Vol. 1513. Cambridge University Press (2013).

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  • Magee, A., and Ladani, L. "Strength and Failure of Ultrafine Grain and Bimodal AlMg Alloy at High Temperatures." Light Metals 2013 (2013): 277-282.

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  • Abdelhadi, O., and Ladani, L., "Mechanical properties of single grain Cu6Sn5 intermetallic compound (IMC) using combined nanoindentation and electron backscatter diffraction (EBSD) imaging," 2013 TMS Annual Meeting & Exhibition, March 2013, San Antonio, TX,.

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  • Abdelhadi, O., and Ladani, L., "Formation of h and ε phases of intermetallics in SnAgCu-Substrate soldering system under structurally constrained condition," 2012 ASME Early Career Technical Conference, ASME ECTC, November 2 – 3, Atlanta, Georgia USA.

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  • Abdelhadi, O., and Ladani, L., "Enhanced EBSD imaging of multi-layer specimen through optimum specimen preparation: application to lead-free solder joints," 2012 ASME Early Career Technical Conference, ASME ECTC, November 2 – 3, Atlanta, Georgia USA.

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  • Magee, A., and Ladani, L. "Mechanical Characterization of Bimodal Grain Size Aluminum 5083 under Various Test Conditions." ICAA13: 13th International Conference on Aluminum Alloys. John Wiley & Sons, Inc (2012).

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  • Harvey, E., and Ladani, L., " Nano-scale characterization of Al-Mg nanocrystalline Alloys," 13th International Conference on Aluminum Alloys (ICAA -13) June 3-7, 2012, Carnegie Mellon University, Pittsburgh, Pennsylvania.

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  • Ladani, L., and Preston, D., " In vivo mechanical characterization of micro-specimens using a novel micro-electro-mechanical system," ASME Summer Bioengineering Conference, Farmington PA., June 22-25, SBC2011-53338,

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  • Gyllenskog, J., and Ladani, L., “Fatigue life analysis of T-38 aileron lever using a continuum damage modeling approach,” IMECE2010-39294, ASME IMECE 2010, Vancouver, BC, Canada.

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  • Abdelhadi, O., and Ladani, L., “Analytical modeling of interfacial shear and peeling stresses in notched multilayered assembly in 4-point bending test,” IMECE2010-37376,  ASME IMECE 2010, Vancouver, BC, Canada.

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  • Ladani, L., Razmi, J., and Bentley, J., “Crack initiation and propagation analysis of the intermetallic compound Cu6Sn5,” IMECE2010-37115, ASME IMECE 2010, Vancouver, BC, Canada.

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  • Nelson, S., and Ladani, L., “Plasticity and damage in bimodal grain size Al-5083 with varied levels of coarse grain content: micro-structural finite element and experiment,” IMECE2010-37310, ASME IMECE 2010, Vancouver, BC, Canada.

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  • Ladani, L., “Damage initiation and propagation modeling using Energy Partitioning Damage Evolution (EDPE) model,” Institute of Electrical and Electronics Engineers, Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, June 2010, Las Vegas, NV.

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  • Ladani, L., and Razmi, J., “Stochastic fatigue damage evolution modeling for visco-plastic materials in micro-electronics,” Institute of Electrical and Electronics Engineers, Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, June 2010, Las Vegas, NV.

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  • Ladani, L., and Razmi, J., “Characterization of SnAg-Based solid liquid inter-diffusion bonds for 3-dminesional integrated circuits,” IMC GROWTH IN SOLID-LIQUID INTERDIFUSSION BONDS American Society of Mechanical Engineering, Intersociety Institute of Electrical and Electronics Engineers Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, June 2010, Las Vegas, NV.

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  • Lyon, P.E., Lambert, M.D., Fronk, T.H., Folkman, S.L., and Ladani, L., “Dimensional stability modeling of cylindrical adhesive joints,” 42nd ISTC - Salt Lake City, UT - October 11-14, 2010.

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  • Ladani, L., and Razmi, J., “Bonding strength and microstructure of SnAg-based solid liquid inter-diffusion bonds,” American Society of Mechanical Engineering, International Mechanical Engineering Congress and Exposition, IMECE 2009, IMECE2009-11454, Nov. 2009, Lake Buena Vista, Fl.

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  • Ladani, L., and Razmi, J., “Interaction effect of voids and standoff height on thermo- mechanical durability of BGA solder joints,” American Society of Mechanical Engineering, International Mechanical Engineering Congress and Exposition, IMECE 2009, IMECE2009-11471, Nov. 2009, Orlando, Fl

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  • Ladani, L., “Effect of design parameters on thermo-mechanical stresses in 3D ICs” American Society of Mechanical Engineering Interpack conference, IPACK2009-89083, July 2009, San Francisco, CA

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  • Ladani, L., and Rodriguez, O., “Thermo-mechanical reliability of through silicon vias (TSVs) and solder interconnects in 3-dimensional integrated circuits,” American Society of Mechanical Engineering Interpack Conference, IPACK2009-89056, July 2009, San Francisco, CA 

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  • Ladani, L., and Razmi, J., “A Mechanical fatigue damage evolution model for PB-Free solder materials,” American Society of Mechanical Engineering, International Mechanical Engineering Congress and Exposition, IMECE 2008-6100, Nov. 2008. Boston, MA.

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  • Ladani, L., “Failure site transition in Pb-Free solder joints caused by manufacturing variabilities in BGA and MLF components in low cycle fatigue analysis,” Society for the Advancement of Materials and Process Engineering, Society for Advancement of Material and Process Engineering (SAMPE) annual conference, SAMPE 2008, May 18 – 22, Long Beach, CA

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  • Ladani, L., and Dasgupta, A., “Partitioned cyclic fatigue damage evolution model for Pb-free solder materials”, American Society of Mechanical Engineers (ASME) Pressure Vessels and Piping Conference; International Conference on Creep and Fatigue at Elevated Temperatures(CREEP8), PV2007-26306, July 2007,  San Antonio, TX  

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  • Askari, F., Ladani, L., Dasgupta, A., Rahko, M., and Sarkka, J., “Effect of design variables on voids and thermal performance of QFN packages,” The ASME 2007 InterPACK Conference (InterPACK'07), and The 7th ASME-JSME Thermal Engineering and Summer Heat Transfer Conference (HT 2007), 32067, July  2007, Vancouver, BC, Canada

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  • Ladani, L., and Dasgupta, A., Cardoso, A., Monlevade, E., “Effect of manufacturing variables on thermo-mechanical durability of Pb-free solders,” American Society of Mechanical Engineering, International Mechanical Engineering Congress and Exposition, IMECE2006-13963, Nov. 2006, Chicago, IL

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  • Ladani, L., and Dasgupta, A., “The successive-initiation modeling strategy for modeling damage progression: application to voided solder interconnects”, 7th. Int. Conf. on Thermal, Mechanical and Multi-physics Simulation and Experiments in Micro-Electronics and Micro-Systems, EuroSimE 2006, 9120112, pp. 1-6, April 2006, Milano, Italy

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  •  Ladani, L., and Dasgupta, A., “Effect of voids on thermo-mechanical durability of Pb-free BGA solder joints: modeling and simulation”, American Society of Mechanical Engineering, International Mechanical Engineering Congress and Exposition, IMECE2005-80238, Nov. 2005, Orlando, FL

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  • Ladani, L., Das, D., Cartwright, J., and Yenkner, B, “Celestica Implementation of Six Sigma Quality System”, Proceeding of International Conference on Six Sigma, December 2004, Glasgow, Scotland.


Current Research Projects
         
A Novel Cu/CNT Material System for Through Silicon Via Interconnects
 
The objectives of this project is to develop and examine a new material system for interconnects used inmicro/nanoelectronics. The material system proposed in this study is expected to overcome several issues of current copper  interconnects. It will make it possible to fabricate nanoscale interconnects with a low resistance and high strength and provide a durable solution for next generation of nano-interconnects. Utilizing advanced micro/nanofabrication processes, carbon nanotubes (CNTs) will be grown inside through silicon vias and copper matrix will be added to enhance the density, strength and conductivity of the CNTs. Electrical and mechanical tests and simulations will be used to evaluate the reliability and electrical functionality of the interconnects.

 
Size and Anisotropy Effects in Micro/Nano-bonds with Comparable Grain and Bond Sizes

T
his project focuses on understanding the kinetics of bond formation and the associated mechanical behavior of different phases that are formed in micro/nanoscale bonds with comparable structural and microstructural sizes. Additionally, we aim to establish a scientific relationship between the microstructure and governing mechanisms of damage and deformation and mechanical properties and fatigue behavior.

Selected Publications:

Abdelhadi, O. and Ladani, L., 2012. IMC growth of Sn-3.5Ag/Cu system: combined chemical reaction and diffusion mechanisms. Journal of Alloys and Compounds, 537, pp. 87-99.

Abdelhadi, O., and Ladani, L., 2013. Mechanical properties of single grain Cu6Sn5 intermetallic compound (IMC) using combined nanoindentation and electron backscatter diffraction (EBSD) imaging. 2013 TMS Annual Meeting & Exhibition.

Anisotropic Deformation and Damage Mechanisms in Al-Mg Bi-modal Grain Size Alloy

Nanocrystalline and ultrafine grain metals show remarkable mechanical behavior at room temperature. However, their behavior at high temperatures are not well understood. The project goals have been to understand governing mechanisms of deformation in these materials under different types of loading conditions including high temperatures. The results are used to design and optimize the materials microstructure for high strength high ductility metals for variety of applications.


Selected Publications:

Magee, A., Ladani, L., Toping, T., and Lavernia, E.J., 2012. Effects of Tensile Test Parameters on the Mechanical Properties of a  Bimodal Al-Mg Alloy. Acta Materialia.

Harvey, E. and Ladani, L., 2012. Complete mechanical characterization of nanocrystalline Al-Mg alloy using nanoindentation. Mechanics of  Materials, 52, pp. 1-11.

Electron beam additive fabrication technology for rapid manufacturing of space vehicle hardware
  The overall goal of the proposed research is to achieve fundamental scientific understanding of the EBAF process and to broaden its effective usage for rapid manufacturing (RM) of space vehicle hardware. Mechanical behavior of parts produced using EBAF process will be examined at different scales and variety of load conditions.  



Past Research Projects
         
Fatigue Damage in T-38 Aileron Lever
Crack initiation and propagation due to cyclic mechanical fatigue damage in the T-38 aileron lever is modeled using a continuum damage modeling approach in conjunction with a “successive initiation” technique. “Successive initiation” is a continuum based damage propagation methodology that is based on updating the state of damage in material and accumulating damage in individual elements according to their stress-life history.  This approach successfully predicts the location of crack initiation, propagation path and propagation rate.  
         
Microstructural Finite Element of Fatigue Crack Initial and Propagation in Bi-Modal Grain Size Alloys
A fatigue crack propagation model was developed for bi-modal grain size alloys and damage model constants for bi-modal grain size aluminum were generated. The model was then used in 2D and 3D microstructural finite element models to model crack initiation and propagation. Grains with different properties were modeled using global-local modeling approach.  
         
Reliability of RFN/MEMS for High Power Application
This research  focused on modeling and simulation of RF M/NEMS contact switches and to determine the critical factors that may affect the surface degradation thereby causing failure due to friction or increased contact resistance.  
         
Development of a crack Sensor for High Temperature Applicaiton
Crack sensors are used to detect crack initiation and propagation in different structures due to different types of environmental loading. The proposed research plan is for initiation and development of a crack sensor for high temperature applications, such as reactors and furnaces in energy conversion systems where available techniques are not feasible. The focus was on micro scale application which resulted in design of a micro scale sensor for evaluating the state of damage in micro scale materials.  
         
Effects of Manufacturing variables on Quality and Durability of Pd-Free solder Interconnects
In summary there were two objectives to this study; first to investigate the effect of manufacturing variability on generation of defects and effect of defects, in particular voids, on thermo-mechanical durability of Pb-free solder joints and second to investigate the impact of design variables on generation of defects and impact of defects, in particular voids, on thermal performance of the micro joints. Both experiment and finite element modeling and simulation were carried out.  
         
Development of Hybrid Level Screening Methodology
The main objectives of this project was to assess the effectiveness of burn-in for hybrid microcircuits and feasibility of reducing burn-in time, review influence of assembly defects on durability of Sn/Pb interconnects and set up a test plan to study the effect of manufacturing variabilities on durability of lead-free solder interconnects. The study was conducted on hybrid pacemaker packages.  
         
In Vivo Mechanical Stimulations of Nerves and Tissues using Novel Micro-electro Mechanical System
The goal of this project was to develop a micro-bio-electromechanical system that can be used to determine the mechanical behavior of tissues at microscale