首页|Revealing the ductile-to-brittle transition mechanism in polycrystalline body-centered tetragonal tin (Sn) for cryogenic electronics
Revealing the ductile-to-brittle transition mechanism in polycrystalline body-centered tetragonal tin (Sn) for cryogenic electronics
扫码查看
点击上方二维码区域，可以放大扫码查看
原文链接
NSTL
Elsevier
? 2022 Elsevier B.V.The inherent ductile-to-brittle transition (DBT) of body-centered tetragonal Sn at cryogenic temperatures restricts the use of Sn-based solders in the interconnection of cryogenic electronics, but little is known about the deformation behaviors accompanying with the transition and the underlying transition mechanism. In this work, the deformation features before cryogenic brittle fracture and the DBT mechanism in polycrystalline Sn were studied through uniaxial tensile experiments at different temperatures. Compared to the softening process stimulated by dynamic recovery and dynamic recrystallization before ductile fracture at room temperature (~293 K), a high strain hardening rate (~5% of the shear modulus) is maintained during the linear hardening period preceding brittle fracture at the liquid nitrogen temperature (~77 K) due to the pronounced intersecting of {301} deformation twins. But the irreconcilable velocity difference between dislocation glide (~3 μm/s) and twin thickening (~10 μm/s) at 77 K leads to a premature brittle fracture in the midst of the linear hardening, and indeed the DBT. The suggested specific DBT mechanism is substantiated by the fact that a significant increase in the velocity (~1500 μm/s) with the increasing temperature (123 K) allows the dislocation slip to readily accommodate the shear strains due to {301} twin thickening at the grain boundaries, thereby resulting in ductile fracture rather than brittle fracture. This deep understanding about the DBT in polycrystalline Sn may help forge a new path to design ductile and strong Sn-based solders and solder joints for cryogenic electronics by deformation twinning.
Cryogenic electronicsDeformation twinningDislocation glideDuctile-to-brittle transitionPolycrystalline Sn
Ji X.、Zhou W.、Guo F.、Wang C.、An R.、Zhong Y.
展开 >
Faculty of materials and manufacturing Beijing University of Technology
State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology
Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education Harbin Institute of Technology
Department of Mechanical Engineering University of South Florida
NSTL
Elsevier
