锰对铸造Zn-38Al-2.2Cu合金组织和热疲劳性能的影响

在Zn-38Al-2.2Cu合金中加入不同量的锰后,研究锰对合金力学性能和显微组织的影响。结果表明,合金中添加0.6%的锰后,部分锰元素溶入基体α′相,使α′相产生固溶强化,导致合金的耐热性及热疲劳性能提高。剩余的锰在基体上析出弥散度和热稳定性都很高的富锰相,提高了合金的热强性,弥补了高温环境下合金晶界薄弱的缺点。富锰相大小适中、分布均匀,对裂纹的传播和扩展有抑制作用,而当富锰相粗大、呈连续状分布时,有利于裂纹的扩展。

Effect of Manganese on Microstructures and Thermal Fatigue Properties of Zn-38Al-2.2Cu Casting Alloy

The effect of adding manganese element in Zn-38Al-2.2Cu alloy on its mechanical properties and microstructures was investigated. The results show that with 0.6% addition of manganese element in Zn-38Al-2.2Cu alloy solution, part of manganese dissolves into matrix to enhance matrix, resulting in an obvious improvement of microstructures, thermal stability and thermal fatigue properties obviously. Heat resistance of the alloy is improved by high dispersity and thermal stability Mn-rich phases which is precipitated in matrix, and, the weak link of alloy grain boundary is avoided. Crack propagation and extension can be restrained by uniformly distributed Mn-rich phase with moderate size. On the contrary, bulky Mn-rich phase in continuous distribution facilitates propagation of crack.