The crystallographic texture, thermal conductivity, and microhardness of the Cu-2.4Ni-0.7Si alloy processed by selective laser melting (SLM) were investigated. The SLM sample shows columnar grains with stronger (100) preferred orientation, and the content of high-angle grain boundaries (HAGBs) is 64.6%. It owns the lower microhardness of 89.73 Hv and the higher thermal conductivity of 187.83 W/m K. After heat treatment for 12 and 25 h, the microstructure of the samples changes from the coarser columnar grains to the smaller equiaxedlike grains with the HAGBs of 59.6% and 61.8%, which show (100), (101), and (111) orientations equally then exhibit stronger (101) and (111) preferred orientation. Moreover, the precipitates vary from Ni3Si with a size of 0.5 μm to Ni2Si with a size of 1 μm, hence resulting in higher microhardness of 180.02 and 170.03 Hv. Due to the precipitates, lower texture index and HAGBs’ content that generate the more grain boundary scattering for electron and phonon transport lead to lower thermal conductivity of 161.57 and 177.83 W/m K. This study suggests that thermal conductivity and microhardness of the SLM Cu-Ni-Si alloy can be tailored by controlling suitable heat treatment condition.

中文翻译：

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通过选择性激光熔化和适当的热处理来提高 Cu-2.4Ni-0.7Si 合金的硬度和中等热导率

研究了选择性激光熔化 (SLM) 处理的 Cu-2.4Ni-0.7Si 合金的晶体织构、热导率和显微硬度。SLM样品显示柱状晶粒具有更强的（100）择优取向，高角晶界（HAGBs）含量为64.6%。它具有 89.73 Hv 的较低显微硬度和 187.83 W/m K 的较高热导率。 经过 12 和 25 h 的热处理后，样品的显微组织从较粗的柱状晶粒变为较小的等轴状晶粒，HAGB 为 59.6 % 和 61.8% 显示 (100)、(101) 和 (111) 取向，然后表现出更强的 (101) 和 (111) 优先取向。此外，析出物从尺寸为 0.5 μm 的 Ni3Si 到尺寸为 1 μm 的 Ni2Si，从而导致更高的显微硬度为 180.02 和 170。03 高压 由于析出物、较低的织构指数和 HAGBs 的含量会产生更多的电子和声子传输的晶界散射导致较低的热导率 161.57 和 177.83 W/m K。这项研究表明 SLM Cu 的热导率和显微硬度-Ni-Si合金可以通过控制合适的热处理条件来定制。