Abstract

Cu-0.25Se-0.25Te alloy has been melted in a vacuum induction furnace and then heat treated. Afterwards, equal-channel angular pressing (ECAP) and subsequent annealing were carried out on the obtained samples. The effects of the ECAP process and subsequent annealing on the microstructure and properties of the alloy have also been investigated by scanning electron microscopy, Vickers microhardness testing, and eddy-current conductivity measurements. The results suggest a morphological evolution of the grains during the ECAP process. The equiaxed grains of the heat-treated alloy initially developed into shapes elongated along the shearing plane, then a series of smaller streamlined strip-like grains appeared and were eventually crushed into fine and equiaxed grains with a size of about 5 μm after different numbers of ECAP passes (one, two, four, or eight), along with a deformed strain ε. Furthermore, the microhardness (HV) rose sharply from 68 N/mm² to 140 N/mm² and then climbed steadily to 169 N/mm² under the comprehensive effect of ε and the refinement of deformed grains. By contrast, the electrical conductivity decreased slowly from 96.2% international annealing copper standard (IACS) to 93.5% IACS. The microhardness and the electrical conductivity of the samples were found to vary contrarily with the change of annealing temperature and stabilized at 500°C. Notably, the electrical conductivity increased gradually, whereas the hardness of the alloys that were subject to a higher number of ECAP passes decreased remarkably with increasing annealing time at 300°C.

中文翻译：

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ECAP工艺及后续退火对Cu-0.25Se-0.25Te合金组织和性能的影响

摘要

Cu-0.25Se-0.25Te合金已在真空感应炉中熔化，然后进行了热处理。之后，对获得的样品进行等通道角压（ECAP）和随后的退火。还通过扫描电子显微镜，维氏显微硬度测试和涡流电导率测量研究了ECAP工艺及其后续退火对合金的组织和性能的影响。结果表明在ECAP过程中晶粒的形态演变。热处理合金的等轴晶粒最初发展成沿剪切面拉长的形状，然后出现了一系列较小的流线型条状晶粒，最终被压碎成细小的等轴晶粒，尺寸约为 5μ在经过不同数量的ECAP（一，二，四或八）之后的m处，以及变形的应变ε。此外，在ε的综合作用下，显微硬度（HV）从68 N / mm ²急剧上升至140 N / mm ²，然后稳定上升至169 N / mm ²。和变形晶粒的细化。相比之下，电导率从96.2％的国际退火铜标准（IACS）缓慢降低至93.5％的IACS。发现样品的显微硬度和电导率与退火温度的变化相反地变化并且稳定在500℃。值得注意的是，电导率逐渐增加，而经过300次ECAP次数较多的合金的硬度却随着300°C退火时间的增加而显着降低。