ABSTRACT

The effect of deformation before aging on discontinuous precipitation in Cu–4.75wt%Ni–1.13wt%Si and Cu–6wt%Ni–1.42wt%Si alloys after solution treatment was investigated. Two kinds of deformation, one under and the other over the uniform deformation limit were implemented after solution treatment. With increasing deformation strain in both alloys, the discontinuous precipitation is accelerated and the aging time for a fully covered region by discontinuous precipitation is shortened. However, the Cu–6wt%Ni–1.42wt%Si alloy deformed under the uniform deformation limits showed an enhanced discontinuous precipitation compared to that for the alloy deformed over the uniform deformation limit. The deformation defects including dislocations and shear bands play the role of encouraging discontinuous precipitation. The shear bands formed during prior deformation beyond the necking point could provide sites for discontinuous precipitation initiation in the early stages of annealing However, shear bands tend to hinder the advance of discontinuous precipitation with further aging in the Cu–Ni–Si alloy with a high content of Ni and Si.

摘要

研究了固溶处理后Cu–4.75wt％Ni-1.13wt％Si和Cu-6wt％Ni-1.42wt％Si合金中时效变形对不连续析出的影响。固溶处理后，实现了两种变形，一种低于均匀变形极限，另一种超过均匀变形极限。随着两种合金中变形应变的增加，不连续沉淀得到加速，不连续沉淀对完全覆盖区域的时效时间缩短了。但是，与在均匀变形极限范围内变形的合金相比，在均匀变形极限范围内变形的Cu–6wt％Ni–1.42wt％Si合金显示出增强的不连续沉淀。包括位错和剪切带在内的变形缺陷起着促进不连续沉淀的作用。