Mechanical Characterization of Copper-Copper Wires Joined by Friction Welding Using Instrumented Indentation Technique
Mechanical Characterization of Copper-Copper Wires Joined by Friction Welding Using Instrumented Indentation Technique
复制标题
DOI：
10.1007/s11665-014-1204-4
复制
发表时间：
2014-08
影响因子：
2.3
通讯作者：
M. Morales;E. Xuriguera;M. Martínez;J. A. Padilla;J. Molera;N. Ferrer;M. Segarra;F. Espiell
中科院分区：
文献类型：
--
作者：
M. Morales;E. Xuriguera;M. Martínez;J. A. Padilla;J. Molera;N. Ferrer;M. Segarra;F. Espiell
采用仪器压痕技术和拉伸试验对火精高导电性（FRHC）和电韧螺距（ETP）铜合金丝的摩擦焊试样进行了力学表征。在纳米/微米尺度上研究了焊接态FRHC-FRHC和ETP-ETP试样在垂直于焊缝界面的中心和外围区域的硬度分布。用光学显微镜和扫描电镜观察了焊缝的显微组织。结果表明：典型的摩擦焊接区为界面区、热机械影响区（TMAZ）和热机械影响区与母材区（BMZ）之间的过渡区，其显微组织和硬度接近母材；没有观察到热影响区的存在。虽然两种焊缝的硬度分布趋势相同，但FHRC-FHRC焊缝的TMAZ比ETP-ETP焊缝窄，随着距离焊接中心线的增加，硬度下降的幅度更大，中心区与外围区的硬度差异更大。ETP-ETP焊缝的拉伸试验表明，试样均在远离焊接接头界面的BMZ处断裂，而FRHC-FRHC焊缝在低强度的TMAZ处断裂。FHRC-FHRC焊缝在力学性能上的这些显著差异可能是由其显微组织性能的较大变化引起的。因此，在工业冷拔线材的典型拉伸应力下，FHRC-FHRC焊缝的焊接失效是合理的。
Friction welding samples of both the fire-refined high-conductivity (FRHC) and electrolytically tough pitch (ETP) copper alloy wires have been mechanically characterized by instrumented indentation technique and tensile test. Hardness profiles in the perpendicular direction to the weld interface, in both the central and peripheral zones, of the as-welded FRHC-FRHC and ETP-ETP samples have been investigated at nano-/micrometric scale. The microstructures of welds have been observed using both the optical microscopy and scanning electronic microscopy. The results show the typical friction welding zones: the interface zone, the thermo-mechanically affected zone (TMAZ), and the transition zone between the TMAZ and the base metal zone (BMZ) that present a microstructure and hardness close to the base metal. No presence of a heat-affected zone is observed. Although both welds show the same tendency in hardness distribution, FHRC-FHRC weld presents a TMAZ narrower than ETP-ETP one, which produces a stronger drop in hardness with increasing of the distance from welding central line, and a higher difference in hardness between the central and peripheral zones. The tensile tests of ETP-ETP welds showed that all samples broke by the BMZ that is far away from the interface of the welded joint, while the most of the FRHC-FRHC welds are broken at the TMAZ region at low strengths. These appreciable differences in mechanical properties for the FHRC-FHRC welds are probably generated by a stronger variation in their microstructural properties. Therefore, it may justify the welding failures in the FHRC-FHRC weld at the typical tensile stress for an industrial cold-drawn process of wires.