微量Cr和Nb对Al-Zn-Mg-Cu-Zr合金力学性能和应力腐蚀性能的影响

Effects of trace Cr and Nb additions on mechanical properties and stress corroded cracking of Al-Zn-Mg-Cu-Zr aluminium alloy

通过金相显微分析、硬度、强度和应力腐蚀性能的测试,研究添加微量Cr和Nb对Al-Zn-Mg-Cu-Zr合金力学性能、再结晶与应力腐蚀行为的影响。结果表明,在Al-Zn-Mg-Cu-Zr合金中添加微量Cr和Nb能提高合金的抑制再结晶能力,并显著提高合金的抗应力腐蚀性能,使合金在保持高的强度和塑性的同时,应力腐蚀临界应力强度因子KISCC由9.8 MPa.m1/2提高到15.2 MPa.m1/2。

The effects of Cr and Nb additions on mechanical and stress corrosion cracking properties of Al-Zn-Mg-Cu-Zr aluminium alloy were investigated by microscopy, hardness, tensile test and stress corrosion cracking test. The results show that the Cr and Nb additions to high strength Al-Zn-Mg-Cu-Zr aluminum alloys can significantly inhibite recrystallization during solution treatment. The tensile and yield strengths, elongation, hardness, stress corrosion cracking resistance of the Cr and Nb containing alloys are moderately improved, comparing with the alloys without Cr and Nb additions. By Cr and Nb additions the critical stress intensity （KISCC） is enhanced from 9.8 MPa.m^1/2 up to 15,2 MPa·m^1/2 with maintaining high strength and ductility.