H62铜合金和T2纯铜不同塑性应变状态微结构演变及其力学性能

对相同退火温度和相同尺寸的T2纯铜板和H62铜合金进行单向拉伸试验,分析两种材料在不同应变状态下对损伤度的影响。结果表明,T2纯铜和H62铜合金的断裂与损伤与其在拉伸作用微结构演变密切相关,微结构的演变对认识两种材料的断裂机理非常重要。两种材料的形状因子随着应变增大具有相似的变化趋势,但不同的是H62铜合金形状因子较大并且快速增大,而T2纯铜的形状因子较小并且缓慢增大。两种材料相对形状因子的变化非常相似,形状因子的相对增长趋势完全一致。H62铜合金比T2纯铜较早进入塑性变形阶段,并且比T2纯铜的塑性变形阶段较短。在突破一定阈值以后,比T2纯铜更快发生破坏变形。通过指数函数对两种材料的归一化形状因子曲线进行了拟合,建立了拟合方程,揭示材料宏观变形与微结构之间的关系。

Microstructure evolution and mechanical properties of H62 copper alloy and T2 pure copper in different plastic strain under tensile loading

Uniaxial tensile tests were carried out on T2 pure copper plate and H62 copper alloy subjected to identical heat treatment. The influences of different strain states on the damage degree of both materials were analyzed. It is found that the fracture and damage of T2 pure copper and H62 copper alloy were closely related to their microstructure under tensile loading. The shape factor of the studied materials showed a similar variation trend with increasing strain, while the shape factor of H62 copper alloy was larger than that of T2 pure copper and increased rapidly as compared to T2 pure copper. The relative shape factor of the studied materials showed very similar variation. H62 copper alloy entered the plastic deformation earlier than T2 pure copper, and hence its plastic deformation stage was shorter than that of T2 pure copper. Beyond a certain threshold, damage and deformation of H62 occurs faster than T2 pure copper. By virtue of exponential function, the normalized shape factor curves of the studied materials were fitted and the fitting equations were established, which revealed the relationship between the macroscopic deformation and microstructure of materials.