In situ X-ray observation and simulation of ratcheting-fatigue interactions in solder joints

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• 作者：Liting Shi ; Yunhui Mei ; Gang Chen ; Xu Chen
• 关键词：in situ ; ratcheting ; fatigue ; X ; ray ; damage ; coupled ; Sn ; 3Ag ; 0.5Cu (SAC305)
• 刊名：Electronic Materials Letters
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：13
• 期：1
• 页码：97-106
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Optical and Electronic Materials; Condensed Matter Physics; Nanotechnology and Microengineering; Characterization and Evaluation of Materials; Nanotechnology;
• 出版者：The Korean Institute of Metals and Materials
• ISSN：2093-6788
• 卷排序：13

文摘

Reflow voids created by solder oxidation reduce the reliability of lap joints. In situ visualization of reflow voids in Sn-3Ag-0.5Cu (SAC305) lap-shear solder joints under cyclic stressing was realized by X-ray computed tomography (CT), while the ratcheting deformation of the solder joints was monitored by a non-contact displacement detecting system (NDDS). The results revealed that the shape evolution of reflow voids in solder joints, as characterized by the sphericity of the voids, can be divided into three stages: i.e., the initial stage with a sharp drop, a stable stage, and a rapidly declining stage. A new evolution law for describing the progress of sphericity was proposed, and was further introduced into a viscoplastic constitutive model based on the OW-AF nonlinear kinematic hardening rule. The damage-coupled OW-AF model yielded an accurate estimation of the whole-life ratcheting behavior of Sn-3Ag-0.5Cu (SAC305) lap-shear solder joints.