High Strain Rate Mechanical Properties of SAC-Q Solder for Extreme Temperatures After Exposure to Isothermal Aging Up to 90 Days

2021 ◽  
Author(s):  
Pradeep Lall ◽  
Vishal Mehta ◽  
Jeffrey C. Suhling ◽  
Ken Blecker
Keyword(s):  
Mechanical Properties ◽  
Oil And Gas ◽  
High Strain ◽  
Strain Rates ◽  
Solder Alloys ◽  
Aerospace Medical ◽  
Free Solder ◽  
Electronic Parts ◽  
Sac Solder ◽  
Temperature Storage

Abstract In many industries, such as automotive, oil and gas, aerospace, medical technologies, electronic parts can often be exposed to high strain loads during shocks, vibrations and drop-impact conditions. Such electronic parts can often be subjected to extreme low and high temperatures ranging from -65oC to 200oC. Also, these electronic devices can be subjected to strain rates of 1 to 100 per second in the critical environment. Recently, many doped SAC solder alloys are being introduced in the electronic component e.g. SAC-Q, SAC-R, Innolot, etc. SAC-Q is made with addition of Bi in Sn-Ag-Cu are composition. Mechanical characteristic results and data for lead-free solder alloys are extremely important for optimizing electronic package reliability, at high temperature storage and elevated strain rates. Furthermore, the mechanical properties of solder alloys can be changed significantly due to a thermal aging, which is causing modification of microstructure. Data for the SAC-Q solder alloy with a high temp aging and testing at extreme low to high operating temperatures are not available.

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.

High Strain Rate Mechanical Properties of SAC-Q Between -65°C and +200°C After Exposure to Isothermal Aging

2020 ◽  
Author(s):  
Pradeep Lall ◽  
Vishal Mehta ◽  
Jeff Suhling ◽  
Ken Blecker
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Isothermal Aging ◽  
High Strain ◽  
Strain Rates ◽  
Solder Alloys ◽  
Stress Strain ◽  
Wide Range ◽  
Operating Temperatures ◽  
Electronic Parts

Abstract In many industries, such as automotive, oil and gas, aerospace, medical technologies, electronic parts can often be exposed to high strain loads during shocks, vibrations and drop-impact conditions. Such electronic parts can often be subjected to extreme low and high temperatures ranging from −65°C to 200°C. Also, these electronic devices can be subjected to strain rates of 1 to 100 per second in the critical environment. Recently, many doped SAC solder alloys are being introduced in the electronic component including SAC-Q, SAC-R, Innolot. SAC-Q is made with addition of Bi in Sn-Ag-Cu composition. Mechanical characteristic results and data for lead-free solder alloys are extremely important for optimizing electronic package reliability, at high temperature storage and elevated strain rates. Furthermore, the mechanical properties of solder alloys can be changed significantly due to a thermal aging, which is causing modification of microstructure. Data for the SAC-Q solder alloy with a high temp aging and testing at extreme low to high operating temperatures are not available. SAC-Q material was tested and analyzed for this study at range of operating temperatures of −65°C to 200°C and at a strain rate up to 75 per second. After the specimens were manufactured and reflowed, specimens were stored at 100°C for the isothermal aging for up to 90 days, before tensile tests were carried out at different operating temperatures. For the wide range of strain rates and test temperatures, stress-strain curves are established. In addition, the measured experimental results and data were fitted to the Anand viscoplasticity model and the Anand constants were calculated by estimating the stress-strain behavior measured in the wide range of operating temperatures and strain rates.

A method for determining the main mechanical properties of soft soils at high strain rates (103–105 s−1) and load amplitudes up to several gigapascals

2005 ◽  
Vol 31 (6) ◽  
pp. 530-531 ◽  
Author(s):  
A. M. Bragov ◽  
A. K. Lomunov ◽  
I. V. Sergeichev ◽  
W. Proud ◽  
K. Tsembelis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Soft Soils

INVESTIGATING THE INFLUENCE OF ENVIRONMENTAL CONDITIONING ON EPOXY RESINS AT QUASISTATIC AND HIGH STRAIN RATES FOR MATERIAL OPERATING LIMIT

2021 ◽  
Author(s):  
SAGAR M. DOSHI, SAGAR M. DOSHI, ◽  
NITHINKUMAR MANOHARAN ◽  
BAZLE Z. (GAMA) HAQUE, ◽  
JOSEPH DEITZEL ◽  
JOHN W. GILLESPIE, JR.
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Yield Stress ◽  
High Strain ◽  
Operating Conditions ◽  
Strain Rates ◽  
High Strain Rates ◽  
Stress Strain ◽  
Wide Range ◽  
Environmental Aging

Epoxy resin-based composite panels used for armors may be subjected to a wide range of operating temperatures (-55°C to 76°C) and high strain rates on the order of 103-104 s-1. Over the life cycle, various environmental factors also affect the resin properties and hence influence the performance of the composites. Therefore, it is critical to determine the stress-strain behavior of the epoxy resin over a wide range of strain rates and temperatures for accurate multi-scale modeling of composites and to investigate the influence of environmental aging on the resin properties. Additionally, the characterization of key mechanical properties such as yield stress, modulus, and energy absorption (i.e. area under the stress-strain curve) at varying temperatures and moisture can provide critical data to calculate the material operating limits. In this study, we characterize mechanical properties of neat epoxy resin, SC-15 (currently used in structural armor) and RDL-RDC using uniaxial compression testing. RDL-RDC, developed by Huntsman Corporation, has a glass transition temperature of ~ 120°C, compared to ~ 85°C of SC-15. A split Hopkinson pressure bar is used for high strain rate testing. Quasistatic testing is conducted using a screw-driven testing machine (Instron 4484) at 10-3 s-1 and 10-1 s-1 strain rates and varying temperatures. The yield stress is fit to a modified Eyring model over the varying strain rates at room temperature. For rapid investigation of resistance to environmental aging, accelerated aging tests are conducted by immersing the specimens in 100°C water for 48 hours. Specimens are conditioned in an environmental chamber at 76 °C and 88% RH until they reach equilibrium. Tests are then conducted at five different temperatures from 0°C to 95°C, and key mechanical properties are then plotted vs. temperature. The results presented are an important step towards developing a methodology to identify environmental operating conditions for composite ground vehicle applications.

Pb-free PBGA Design Points to Improve Handling Robustness

2012 ◽  
Vol 2012 (1) ◽  
pp. 000110-000118 ◽  
Author(s):  
Isabel de Sousa ◽  
Brian Roggeman ◽  
Oswaldo Chacon ◽  
Niki Spencer ◽  
Mamoru Ueno
Keyword(s):  
High Speed ◽  
Solder Joints ◽  
High Strain ◽  
Strain Rates ◽  
Process Variables ◽  
Flexural Stress ◽  
High Strain Rates ◽  
Ball Shear ◽  
Laminate Design ◽  
Free Solder

Pb-Free BGA solder joints are more brittle and more susceptible to interfacial fails than the leaded versions. These brittle failures typically occur if the modules are subjected to high strain rates through module handling impacts or PCB flexural stress. The high speed ball shear technique is a useful method to submit solder joints to high strain rates in a controlled manner to emulate the levels of strain the BGAs may see in handling. This measurement technique was used to evaluate different laminate design and process variables on organic laminate substrates to create a more robust Pb-Free solder joint. Experiments were conducted to evaluate the effects and interactions of laminate, module assembly process, SAC alloy composition, and thermal treatments. Modulations of shear speed and shear angle made it possible to observe transitions from ductile to brittle solder fractures. The high speed ball shear method was successful to differentiate subtle effects resulting from different design points and process variables. The copper composition in the PbFree solder alloy, thermal history, and geometric factors such as solder volume, solder resist opening and solder resist thickness all had measurable impacts on the shear strength and transition point of ductile to brittle failure. Some BGA configurations have also been tested in reliability, namely in thermal cycling, and were shown to meet application requirements. Optimal design points can therefore be applied to enhance handling robustness without compromising on reliability.

Nanoindentation Characterization of Lead-free Solders and Intermetallic Compounds under Thermal Aging

2010 ◽  
Vol 2010 (1) ◽  
pp. 000314-000318
Author(s):  
Tong Jiang ◽  
Fubin Song ◽  
Chaoran Yang ◽  
S. W. Ricky Lee
Keyword(s):  
Mechanical Properties ◽  
Thermal Aging ◽  
Solder Joints ◽  
Lead Free ◽  
Small Range ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Aging Test ◽  
Free Solder ◽  
Lead Free Solders

The enforcement of environmental legislation is pushing electronic products to take lead-free solder alloys as the substitute of traditional lead-tin solder alloys. Applications of such alloys require a better understanding of their mechanical behaviors. The mechanical properties of the lead-free solders and IMC layers are affected by the thermal aging. The lead-free solder joints on the pads subject to thermal aging test lead to IMC growth and cause corresponding reliability concerns. In this paper, the mechanical properties of the lead-free solders and IMCs were characterized by nanoindentation. Both the Sn-rich phase and Ag3Sn + β-Sn phase in the lead-free solder joint exhibit strain rate depended and aging soften effect. When lead-free solder joints were subject to thermal aging, Young's modulus of the (Cu, Ni)6Sn5 IMC and Cu6Sn5 IMC changed in very small range. While the hardness value decreased with the increasing of the thermal aging time.

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