正火处理对Cu-A1-Be-B合金阻尼性能和断裂特征的影响

Influence of Normalization on Damping Properties and Cracking Characteristic of Cu-A1-Be-B Alloy

采用扫描电镜、X射线衍射分析等手段 ,研究了正火处理对Cu Al Be B合金组织、相结构及阻尼和力学性能的影响 ,并原位观察拉伸应力作用下裂纹的萌生和扩展过程。研究结果表明 ,Cu Al Be B合金具有较高的阻尼性能 (S D C =17%～ 19% ) ,正火处理可抑制α相的析出 ,并减少γ1′的混杂程度 ,从而进一步提高阻尼能力。各向弹性异性和相变应变差引起的晶界集中应力 ,导致Cu A1 Be B合金在拉伸条件下发生晶间断裂。正火处理不但纯净晶界 ,形成马氏体共格晶界 ,而且减小晶内γ1′马氏体与 β1′马氏体的混合程度 ,有利于减少晶界应力集中和可能萌生的晶界裂纹源 ,从而有效改善合金的塑性和强度。

Compared with as casting,the influence of normalizaton on the microstructure,phase structure,the damping and mechanical properties,as well as the initiation of microcrack and its propagation during in situ tensile of Cu A1 Be B alloy by means of SEM and XRD were investigated.The results indicate that the alloy has a high damping capacity(S.D.C=17%～19%),the upper level ascribed to normalization which restrains the precipitation of α phase and reduces martensite mixture of β 1′and γ 1′.Furthermore,purifying the grain boundary so that the martensite coherent interfaces formed there,and lowing the extent of β 1′ mixed with γ 1′,normalization may soften stress concentration and minish the cracks,both of them usually take place along the polycrystalline boundaries.Therefore the normalization can improve effectively both plasticity and tensile strength of Cu Al Be B alloy.