Evolution of Anand Parameters and High Strain Rate Mechanical Properties of Sac Solder Alloy at Low and High Operating Temperatures

2021 ◽  
Author(s):  
Vikas Yadav ◽  
Pradeep Lall
Keyword(s):  
Mechanical Properties ◽  
High Strain Rate ◽  
Strain Rate ◽  
Solder Alloy ◽  
High Strain ◽  
Operating Temperatures ◽  
Sac Solder

Low Temperature Material Characterization of Lead-Free SAC Solder Alloy at High Strain Rate After Prolonged High Temperature Storage

2021 ◽  
Author(s):  
Pradeep Lall ◽  
Vikas Yadav ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Solder Alloy ◽  
High Strain ◽  
Prolonged Storage ◽  
Solder Alloys ◽  
Snagcu Solder ◽  
Operating Temperatures ◽  
Sac Solder

Abstract During operations, handling, and storage in extreme environmental applications including aerospace, defense and automotive, the electronics may be exposed to high and low operating temperatures. In automotive underhood applications, the temperature can vary especially from −65 to +200 °C. Under prolonged storage, SnAgCu solder materials have been shown to continually evolve in the mechanical properties. New doped SAC solder alloys have recently been introduced with the addition of Ni, Co, Au, P, Ga, Cu and Sb to SAC solder alloy to increase the robustness under prolonged thermal exposure. High strain-rate data on SAC solder alloys after prolonged storage operating at low operating temperatures is not available in published literature. In this paper, materials characterization of SAC (SAC105 and SAC-Q) solder after prolonged storage at low operating temperatures (−65°C–0 °C) and at high strain rates (10–75 per sec) has been studied. The fabricated SAC leadfree solder specimens were isothermally aged up to 12 months at 50°C before testing. Anand Viscoplastic model has been used to compute 9 anand parameters from measured Tensile data to describe the material constitutive behavior. The computed 9 anand parameters were used to verify the accuracy of the Anand model. A good correlation was found between experimental data and Anand predicted data.

High Strain Rate Low Temperature Properties for SAC-R After Exposure to Isothermal Aging

2020 ◽  
Author(s):  
Pradeep Lall ◽  
Mrinmoy Saha ◽  
Jeff Suhling ◽  
Ken Blecker
Keyword(s):  
Mechanical Properties ◽  
High Strain Rate ◽  
Strain Rate ◽  
Storage Temperature ◽  
High Strain ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Aging Effects ◽  
Space Applications ◽  
Sac Solder

Abstract Electronic parts in military, automotive, avionics and space applications may be subjected to sustained operation at high temperature in addition to high strain-rate loads. Parts may be stored in non-climate-controlled enclosures prior to deployment. Earlier studies on undoped SAC alloys have shown that the material properties evolve after prolonged period of storage at even modest temperatures. In order to mitigate the aging effects, a number of alloy formulation have been proposed. Data of the mechanical properties of lead-free solder alloys which is used for interconnection in the electronic packaging at high strain rates and at high storage temperature is very essential for design optimization of electronic package sustainability at extreme temperature environment because the SAC solders have shown to have degradation in mechanical properties at prolonged exposure to storage temperature. Industries have come up with a solution to reduce the degradation using dopants in SAC solder. In this study, a doped SAC solder called SAC-R has been subjected to high strain rate testing after extended storage at temperature of 50°C for 1 month, 2 months and 3 months. Samples with no aging and aged samples for up to 3-months have been subjected to uniaxial tensile tests to measure the mechanical properties of SAC-R for High and Low operating temperature ranging from −65°C to +200°C. The material data has been used to compute the constants for the Anand Visco-Plasticity model. The ability of the model to represent the material constitutive behavior has been quantified by comparing the model predictions of the uniaxial tensile test with the experimental data.

Determination of High and Low Temperature High Strain Rate Mechanical Properties for SAC-R After Exposure to Isothermal Aging of 50°C Up To 8 Months

2021 ◽  
Author(s):  
Pradeep Lall ◽  
Mrinmoy Saha ◽  
Jeff Suhling ◽  
Ken Blecker
Keyword(s):  
Mechanical Properties ◽  
High Strain Rate ◽  
Strain Rate ◽  
Prolonged Exposure ◽  
High Strain ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Aging Effects ◽  
Space Applications ◽  
Sac Solder

Abstract Electronic parts may be subjected to continuous activity at high temperatures as well as high strain-rate loads in the oil exploration industry, military, automotive, avionics, and space applications, and parts may be stored in non-climate-controlled enclosures prior to deployment. Material properties evolve at even moderate temperatures after a long period of storage, according to previous studies on undoped SAC alloys. To reduce the aging effects, a number of alloy formulations have been proposed. Data on the mechanical properties of lead-free solder alloys used for interconnection in electronic packaging at high strain rates and high storage temperatures is very important for design optimization of electronic package sustainability at extreme temperatures, since SAC soldiers have shown degradation of mechanical properties after prolonged exposure to storage temperature. The use of dopants in SAC solder has been proposed as a solution to minimize degradation. In this study, After keeping the samples in storage at 50°C for 1–8 months, a doped SAC solder called SAC-R (Ecolloy) was subjected to high strain rate testing. Uniaxial impact hammer tensile tests were conducted on samples with no aging and samples that had been aged for up to 8 months to assess the mechanical properties of SAC-R at high and low operating temperatures ranging from −65°C to 200°C and the Mechanical properties has been compared with an undoped solder SAC 105. The constants for the Anand Visco-Plasticity model were calculated using the material data for SAC-R. By comparing model predictions of the uniaxial tensile test with experimental results, the model’s ability to reflect material constitutive behavior has been quantified.

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