Experiments were performed to investigate the tensile deformation characteristics of a Cu-2.5 wt% Ni-0.55 wt% Si alloy containing trace elements of Zn, Sn and Mg, processed by high-pressure torsion (HPT) under an applied pressure of 5 GPa for 10 revolutions, and then peak-aged or over-aged at 300 °C. The grain size of the HPT-processed (H) alloy was refined to 70 nm. The peak-aged (PA) alloy exhibited a higher tensile strength σ_u of over 1 GPa than the H alloy. The over-aged (OA) alloy exhibited a lower value of σ_u than not only the PA but the H alloy. The PA and the OA alloy revealed unique tensile deformation properties: an extremely small local elongation of 0.1% for the PA alloy, a very small uniform elongation of 0.2% for the OA alloy, and a sudden drop of tensile stress immediately after necking initiation for the OA alloy. The small local and uniform elongation for the PA and OA alloy were explained on the basis of intergranular fracture after and before necking initiation during tension. The stress drop was caused by the rapid propagation of intergranular fracture from the surface of necking part to the interior. Intergranular segregation of Sn promoted by aging at 300 °C resulted in the intergranular fracture of the PA and OA alloy.

进行实验以研究含有Zn，Sn和Mg的痕量元素的Cu-2.5 wt％Ni-0.55 wt％Si合金的拉伸变形特性，该合金在5 GPa的外加压力下通过高压扭转（HPT）处理旋转10圈，然后在300°C时达到峰值时效或过时效。经HPT处理的（H）合金的晶粒尺寸细化到70 nm。峰值老化（PA）合金呈现出较高的抗拉强度σ _ù以上为1GPa的比H合金。的过时效（OA）合金表现出较低的值σ _ù不仅是PA，还包括H合金。PA和OA合金具有独特的拉伸变形特性：PA合金的局部伸长率极小，为0.1％，OA合金的均匀伸长率，极小，为0.2％，颈缩开始后立即发生突然的拉伸应力下降OA合金。PA和OA合金的小局部和均匀伸长率是根据在拉伸过程中颈缩开始之后和之前的晶间断裂来解释的。应力下降是由于晶间断裂从颈缩部分的表面快速传播到内部而引起的。300°C时效促进了Sn的晶间偏析，导致PA和OA合金的晶间断裂。