Cu-10Cr-0.4Zr形变原位复合材料的组织演变特征

Structural Evolution Characteristics of Cu-10Cr-0.4Zr In-situ Composites

制备了Cu-10Cr和Cu-10Cr-0.4Zr合金,并经冷变形形成了原位复合材料。研究Zr添加剂对合金铸态组织和复合材料的纤维形貌的影响,以及随着形变率的提高β-Cr纤维演变特征。研究表明,在Cu-10Cr合金中添加的0.4%（质量分数）Zr,Cr析出相的直径由15-80μm细化到10-20μm;对Cu-10Cr-0.4Zr合金能谱分析表明,在Cu-10Cr-0.4Zr铸态组织中存在Cu5Zr相的形成和析出;随着形变率增大,β-Cr相之间的间距不断减小,其宽厚比也进一步增大,纤维相发生比较明显的弯曲和扭折,特别是当形变率η=6.2时,纤维相的厚度能够达到250-350nm,纤维相变形和分布也趋于均匀;当η=6.2时,Cu-10Cr-0.4Zr形变复合材料的抗拉强度达到1089 MPa,采用改进的Hall-Petch公式计算其值为1037 MPa,理论计算数值与观测结果基本一致。

The Cu-10Cr alloy,Cu-10Cr-0.4Zr alloy and the in-situ composite based on the alloys were prepared.Microstructures of as-cast,structural evolution characteristics of Cu-10Cr-0.4Zr in-situ composites were investigated.The results showed that the addition of 0.4%（mass fraction）Zr in the Cu-10%Cr gave birth to smaller as-cast Cr dendrites,their diameters were reduced from 15-80μm to 10-20μm;the EDS quantitative analysis of as-cast Cu-10Cr-0.4Zr alloy showed that the Zr-rich phase should be Cu5Zr;with the increasing of drawing strains,the spacings among the β-Cr phases decreased gradually and the thickness of β-Cr phases decreased rapidly,the β-Cr phases were constrained to fold and twist,particularly at η=6.2,the thickness reached 250-350nm;at η=6.2,the predicted strength using Hall-Petch equation was 1037MPa,which was good agreement with the observed strength 1089MPa.