【摘要】 为了研究定向凝固Cu-Cr自生复合材料的微观组织构成及其在不同凝固速度条件下的组织演变,在高梯度定向凝固装置上制备了Cu-1.0%Cr、Cu-1.7%Cr(质量分数)两种成分的Cu基自生复合材料,采用金相显微镜、扫描电镜以及能谱分析进行了微观组织观察和相的成分分析.研究表明:Cu-1.0%Cr亚共晶合金定向凝固组织为初生α相和棒状(或针状)共晶体(α+β)的混合组织;Cu-1.7%Cr过共晶合金为α相、初生β相和共晶(α+β)的混合组织;随着凝固速度的提高,α相一次胞(枝)晶逐渐细化,晶间距逐渐减小;共晶体(α+β)分布在α相胞(枝)晶间,起到强化基体的作用;初生β相呈颗粒状不均匀地分布在α相基体上.更多还原

【Abstract】 The microstructure and its evolution of directionally solidified Cu - Cr in-situ composites are investigated under the condition of the different solidification rates. The Cu - 1.0wt% Cr and Cu - 1. 7wt% Cr in-situ composites respectively were prepared by the high temperature gradient directional solidification equipment. The microstructure is observed with metaloscope and SEM, and its component is analyzed by EDS. The results show that, the microstructures of the hypoeutectic Cu - 1. 0wt% Cr alloy consists of primary α( Cu) phase and the rod-like or needle-like(α+β) eutectics, and the one of the hypereutectic Cu - 1. 7% Cr alloy is of α( Cu) phase,primary β(Cr) phase and (α+β) eutectics. The 1st cellular (dendrite) of α(Cu) phase thins gently and cellular (dendrite) spacing shortens gradually with the increase of the solidification rates. The (α+β) eutectics as the reinforce phase set in α(Cu) cellular or dendrite, and primary β(Cr) phase as particle distribute unevenly on α(Cu) matrix.更多还原