Deformation analysis of lap-shear testing of solder joints

This study investigates the shear strength and aging characteristics of Sn-3.0Ag-0.5Cu (SAC 305)/Cu joints by the addition of ZrO2 nanoparticles (NPs) having two different particle size: 5–15 nm (ZrO2A) and 70–90 nm (ZrO2B). Nanocomposite pastes were fabricated by mechanically mixing ZrO2 NPs and the solder paste. ZrO2 NPs decreased the β-Sn grain size and Ag3Sn intermetallic compound (IMC) in the matrix and reduced the Cu6Sn5 IMC thickness at the interface of lap shear SAC 305/Cu joints. The effect is pronounced for ZrO2A NPs added solder joint. The solder joints were isothermally aged at 175 °C for 24, 48, 144 and 256 h. NPs decreased the diffusion coefficient from 1.74 × 10–16 m/s to 3.83 × 10–17 m/s and 4.99 × 10–17 m/s for ZrO2A and ZrO2B NPs added SAC 305/Cu joints respectively. The shear strength of the solder joints decreased with the aging time due to an increase in the thickness of interfacial IMC and coarsening of Ag3Sn in the solder. However, higher shear strength exhibited by SAC 305-ZrO2A/Cu joints was attributed to the fine Ag3Sn IMC’s dispersed in the solder matrix. Fracture analysis of SAC 305-ZrO2A/Cu joints displayed mixed solder/IMC mode upon 256 h of aging.

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Microstructural and Mechanical Characterization of Solder Joints Fabricated by Explosively Reacting Nanolayers

Volume 13: Nano-Manufacturing Technology; and Micro and Nano Systems, Parts A and B ◽

10.1115/imece2008-68714 ◽

2008 ◽

Cited By ~ 1

Author(s):

Michael Tong ◽

Jenn-Ming Yang

Keyword(s):

Initial Temperature ◽

Mechanical Characterization ◽

Solder Joints ◽

Initial Pressure ◽

Processing Parameters ◽

Joint Shear Strength ◽

Lap Shear ◽

Joint Shear ◽

Solder Interface

The unique heat-releasing characteristics of explosively reactive nanolayers (RN) are used in this study to produce Si/solder/Si joints. The microstructure of the RN in the reacted state as well as the post-joining foil/solder interface is characterized via XRD, SEM, and TEM, which have never been done. Additionally, RN solder joints are mechanically characterized by single lap shear and nanoindentation to obtain a set of optimized processing parameters, specifically initial pressure applied (Pa) and initial temperature of the system (Ti). A maximum joint shear strength of ∼ 30MPa at Pa = 15MPa and Ti = 75°C. Furthermore, nanoindentation is used to clarify the mechanical behavior of individual layers and interfaces across the joints as a result of thermal aging.

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Dynamic Recrystallization of Sn3.0Ag0.5Cu Pb-Free Solder Alloy

Volume 6: Electronics and Photonics ◽

10.1115/imece2008-67671 ◽

2008 ◽

Cited By ~ 3

Author(s):

Ken Holdermann ◽

Gayatri Cuddalorepatta ◽

Abhijit Dasgupta

Keyword(s):

Grain Size ◽

Focused Ion Beam ◽

Solder Joints ◽

Ion Beam ◽

Fatigue Tests ◽

Sac305 Solder ◽

Creep Tests ◽

Lap Shear ◽

Mechanical Cycling ◽

Sac Solder

This study examines microstructural recrystallization in Sn3.0Ag0.5Cu (SAC305) solder joints due to isothermal, mechanical cycling. It is well known that after reflow SAC solder joints at length scales of 200 μm consist of only a few grains [1–3]. This coarse microstructure makes the joint mechanically inhomogeneous and anisotropic, and non-repeatable. Creep tests conducted on modified lap-shear SAC305 solder joints therefore show significant scatter in their results, because of piece-to-piece variability in the microstructural morphology [1]. However, results of cyclic fatigue tests of the same SAC305 solder joints show less significant scatter [4]. One possible hypothesis is that dynamic recrystallization occurs during the cycling, resulting in a much finer (and hence more isotropic, homogeneous and repeatable) microstructure. Recrystallization of solder has been reported to occur under thermal cycling [5–6]. The objective of this study is to assess the extent of recrystallization of SAC305 solder during isothermal mechanical cycling fatigue. Focused ion beam technology is used to prepare a very clean and even surface to reveal the SAC305 grains in modified lap-shear test specimens, both before and after isothermal mechanical cycling. Polarized light microscopy, scanning electron microscopy and focused ion beam microscopy are used to reveal the microstructure of these SAC305 solder joints. The results show that mechanical cycling produces the same type of recrystallization behavior of SAC solder, as has been reported in the literature for thermally cycled specimens [5–6]. The number of grains in the SAC305 solder joint changes from a few to hundreds, during mechanical cycling. As expected, the recrystallization is observed to be localized around cracks in the solder joint, where the local stresses are the highest. The minimal grain size near the cracked region is approximately 4–6 μm and the average grain size increases significantly with increasing distance from the crack face. The transition of solder from very few (non-homogeneous and anisotropic) to a homogenous recrystallized state may be one possible explanation for differences in the extent of scatter in the data from creep tests and isothermal mechanical fatigue tests.

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Ultrasonic Welding of Glass Fiber Reinforced Polypropylene

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.557-559.1313 ◽

2012 ◽

Vol 557-559 ◽

pp. 1313-1316

Author(s):

Jian Guang Zhang ◽

Krishan.K. Chawla ◽

Uday.K. Vaidya

Keyword(s):

Glass Fiber ◽

Ultrasonic Welding ◽

Maximum Strength ◽

Weld Strength ◽

Fiber Reinforced ◽

Shear Testing ◽

Polypropylene Composites ◽

Lap Shear ◽

Glass Fiber Reinforced ◽

Weld Time

Glass fiber reinforced polypropylene composites were joined by ultrasonic welding, employing various weld conditions. Single-lap shear testing was used to evaluate the effect of weld time and weld pressure on the weld performance. The weld strength increased with increasing weld time and weld pressure until a plateau or maximum strength was reached. The required weld time to obtain a complete weld became shorter when the weld pressure was increased. As lower weld pressure was applied, a complete weld could not be obtained unless relatively longer weld times were employed. A welding map, showing conditions of weld time and weld pressure to get a good weld, was obtained.

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A design of a new miniature device for solder joints’ mechanical properties evaluation

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406216654728 ◽

2016 ◽

Vol 231 (20) ◽

pp. 3818-3830 ◽

Cited By ~ 7

Author(s):

Quang-Bang Tao ◽

Lahouari Benabou ◽

Laurent Vivet ◽

Ky-Lim Tan ◽

Jean-Michel Morelle ◽

...

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Strain Rate ◽

Solder Joints ◽

Testing Machine ◽

Testing Temperature ◽

Material Behavior ◽

Shear Strain Rate ◽

Solder Alloys ◽

Lap Shear

This paper makes a focus on the design of a micro-testing machine used for evaluating the mechanical properties of solder alloys. The different parts of the testing device have been developed and assembled in a manner that will facilitate the study of miniature solder joints as used in electronic packaging. A specific procedure for fabricating miniature lap-shear joint specimens is proposed in this work. The tests carried out with the newly developed machine serve to determine the material behavior of solder joints under different controlled loading and temperature conditions. Two new solder alloys, namely SACBiNi and Innolot, are characterized in the study, showing the influence of strain rate and temperature parameters on their respective mechanical responses. In addition, the as-cast and fracture surfaces of the solder joints are observed with a scanning electron microscope to reveal the degradation mechanisms. The SACBiNi solder alloy, which contains less Ni and Sb elements, is found to have smaller shear strength than the Innolot alloy, while its elongation to rupture is significantly improved at the same strain rate level and testing temperature. The highest shear strength is 58.9 MPa and 61.1 MPa under the shear strain rate of 2.0 × 10−2 s−1 and room temperature for the SACBiNi and Innolot solder joints, respectively. In contrast, the lowest shear strength values, 26.6 MPa and 29.5 MPa for SACBiNi and Innolot, respectively, were recorded for the strain rate value of 2.0 × 10−4 s−1 and at temperature of 125℃.

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