Dynamic behavior tests of lead-free solders at high strain rates by the SHPB technique

2008 ◽  
Author(s):  
Qin Fei ◽  
An Tong ◽  
Chen Na
Keyword(s):  
Dynamic Behavior ◽  
High Strain ◽  
Lead Free ◽  
Strain Rates ◽  
High Strain Rates ◽  
Lead Free Solders

Strain Rate Effects and Rate-Dependent Constitutive Models of Lead-Based and Lead-Free Solders

2009 ◽  
Vol 77 (1) ◽  
Author(s):  
Fei Qin ◽  
Tong An ◽  
Na Chen
Keyword(s):  
Strain Rate ◽  
Impact Analysis ◽  
Solder Joints ◽  
High Strain ◽  
Drop Impact ◽  
Lead Free ◽  
Strain Rates ◽  
High Strain Rates ◽  
Rate Dependent ◽  
Lead Free Solders

As traditional lead-based solders are banned and replaced by lead-free solders, the drop impact reliability is becoming increasingly crucial because there is little understanding of mechanical behaviors of these lead-free solders at high strain rates. In this paper, mechanical properties of one lead-based solder, Sn37Pb, and two lead-free solders, Sn3.5Ag and Sn3.0Ag0.5Cu, were investigated at strain rates that ranged from 600 s−1 to 2200 s−1 by the split Hopkinson pressure and tensile bar technique. At high strain rates, tensile strengths of lead-free solders are about 1.5 times greater than that of the Sn37Pb solder, and also their ductility are significantly greater than that of the Sn37Pb. Based on the experimental data, strain rate dependent Johnson–Cook models for the three solders were derived and employed to predict behaviors of solder joints in a board level electronic package subjected to standard drop impact load. Results indicate that for the drop impact analysis of lead-free solder joints, the strain rate effect must be considered and rate-dependent material models of lead-free solders are indispensable.

Tensile Behaviors of Lead-Containing and Lead-Free Solders at High Strain Rates

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Fei Qin ◽  
Tong An ◽  
Na Chen ◽  
Jie Bai
Keyword(s):  
High Strain ◽  
Lead Free ◽  
Strain Rates ◽  
High Strain Rates ◽  
Reliability Design ◽  
Split Hopkinson Tensile Bar ◽  
Rate Dependent ◽  
Before And After ◽  
Split Hopkinson ◽  
Lead Free Solders

Behavior of solder joints in microelectronic packages is crucial to the drop impact reliability design of mobile electronic products. In this paper, tensile behaviors of Sn37Pb, Sn3.5Ag, and Sn3.0Ag0.5Cu at strain rates of 600 s−1, 1200 s−1, and 1800 s−1 were investigated using the split Hopkinson tensile bar experimental technique. Stress-strain curves of the three solders were obtained, and microstructure and fractography of the specimens before and after the tests were examined and presented. The experimental results show that the lead-free solders are strongly strain rate dependent: Their tensile strength, percent elongation, and percent reduction in area are much greater than those properties of the lead-containing solder at high strain rates.

Evolution of Anand Parameters With Elevated Temperature Aging for SAC Leadfree Alloys

2019 ◽  
Author(s):  
Pradeep Lall ◽  
Vikas Yadav ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
Thermal Aging ◽  
High Strain ◽  
Lead Free ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
High Strain Rates ◽  
Free Solder ◽  
Sac Solder

Abstract Electronic components in downhole oil drilling and gas industry applications, automotive and avionics may exposed to high temperatures (> 150°C) and high strain rates (1–100 per sec) during storage, operation and handling which can contribute to the failures of electronics devices. Temperatures in these applications can exceed 200°C, which is closed to melting point for SAC alloys. The microstructure for lead free solder alloys constantly evolves when subjected to thermal aging for sustained periods with accompanying degradation in mechanical properties of solder alloys. In this paper, evolution of microstructure and Anand parameters for unaged and aged SAC (SAC105 and SAC-Q) lead free solder alloys at high strain rates has been investigated induced due to thermal aging. The microstructure of the SAC solder is studied using scanning electron microscopy (SEM) for different strain rate and elevating temperature. The thermal aged leadfree SAC solder alloys specimen has been tested at high strain rates (10–75 per sec) at elevated temperatures of (25°C–200°C). The SAC leadfree solder samples were subjected to isothermal aging at 50°C up to 1-year before testing. To describe the material constitutive behavior, Anand Viscoplastic model has been used. Effect of thermal aging on Anand parameters has been investigated. In order to verify the accuracy of the model, the computed Anand parameters have been used to simulate the uniaxial tensile test. FEA based method has been used to simulate the drop events using Anand constitutive model. Hysteresis loop and Plastic work density has been computed from FEA.

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