梯度热处理制备技术加速合金最佳热处理工艺参数筛选

AgCuNiInSn系列电接触合金的合金化程度要求高，需要对合金铸锭进行均匀化热处理来消除铸锭组织中的低熔点非平衡相和枝晶偏析。对于热处理最佳工艺参数的摸索，传统的“试错法”存在实验量巨大、研发周期长、研发效率低等不足。本研究提出一种梯度温度场均匀化热处理高通量制备方法，用于Ag-6Cu-0.5Ni-0.5In-0.5Sn合金最佳均匀化热处理条件筛选。结果表明，经过608.13 ℃/1 h的梯度均匀化热处理，再经过75%的塑形变形后，硬度达到最大值为168.7，合金组织晶粒和第二相体积较小，点状第二相弥散分布较多且均匀，细晶强化效应和弥散强化效应最为显著。

Gradient heat treatment accelerates the screening of optimal process parameters for the heat treatment of an alloy

A high alloying degree is required for AgCuNiInSn series electrical contact materials and it is necessary to perform homogenizing heat treatment on the alloy ingot to eliminate non-equilibrium phases with low melting-point and dendritic segregation in the ingot microstructure. The traditional “trial-and-error” method for finding the optimal process parameters for heat treatment has the defects of huge number of experiments, long cycle and low efficiency. A high-throughput preparation method for homogenizing heat treatment with gradient temperature field was proposed in this paper to screen the optimal treatment conditions for Ag-6Cu-0.5Ni-0.5In-0.5Sn. The experimental results show the maximum hardness of the alloy obtained after 75% plastic deformation by gradient homogenization heat treatment is 168.7, a value corresponding to the optimum homogenization heat treatment temperature of 608.13 °C/1 h. Under the optimal annealing conditions, the volume of grains and the second phase are small, and the distribution of point-like second phase dispersion is more and uniform. At this point, the strengthening effects both from fine grains and dispersions are most significant.