Abstract The plasticity of Fe-6.5Si (wt.%) alloys with additions of 0, 0.3, 0.5 and 0.7 wt% Cu was investigated by tensile tests at intermediate temperatures below 550 °C. It was found that the plasticity of Fe-6.5Si (wt.%) alloy increased with Cu addition to up to 0.3 wt%, but decreased with further increase in Cu addition. When the Cu addition was increased to 0.7 wt%, the plasticity of the alloy became lower than that for the alloy without Cu addition. The reduction of cross-sectional thickness of the tested specimens confirmed that the onset temperatures of brittle to ductile transition were about 90, 262, 304 and 400 °C for Fe-6.5Si (wt.%) alloys with Cu additions of 0.3, 0.5, 0 and 0.7 (wt.%), respectively. Microstructure analysis suggested that the solubility of Cu in the alloy was or higher than 0.3 wt%, but lower than 0.5 wt%. The Cu dissolution in the solid solution increased the plasticity of the Fe-6.5Si (wt.%) alloy as a result of the reduced degree of long-range order. Increasing Cu addition beyond the solid solution limit caused the Cu-rich phase precipitation at grain boundaries, which embrittled the grain boundaries and hence severely reduced the plasticity of the alloy.

中文翻译：

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Cu添加对Fe-6.5Si (wt.%)合金550℃以下塑性的影响

摘要 通过在低于 550 °C 的中间温度下进行拉伸试验，研究了添加 0、0.3、0.5 和 0.7 wt% Cu 的 Fe-6.5Si (wt.%) 合金的塑性。结果表明，Fe-6.5Si (wt.%) 合金的塑性随 Cu 添加量增加至 0.3 wt% 而增加，但随着 Cu 添加量的进一步增加而降低。当Cu添加量增加到0.7wt%时，合金的塑性低于未添加Cu的合金。测试样品横截面厚度的减小证实，对于 Fe-6.5Si（重量百分比）合金，Cu 添加量为 0.3、0.5 时，脆性向韧性转变的起始温度约为 90、262、304 和 400 °C , 0 和 0.7 (wt.%)，分别。显微组织分析表明Cu在合金中的溶解度大于等于0.3wt%，但小于0.5wt%。由于长程有序度的降低，固溶体中的铜溶解增加了 Fe-6.5Si (wt.%) 合金的塑性。超过固溶极限的Cu添加量会导致晶界处富Cu相析出，使晶界脆化，从而严重降低合金的塑性。