含铒铝合金显微组织对疲劳裂纹扩展的影响

The Effect of Microstructure on Fatigue Crack Propagation of Er-containing Aluminum Alloy

摘要:

对含铒铝合金板材进行了不同的热处理工艺，分析了各板材的显微组织结构对疲劳裂纹扩展和力学性能的影响。结果表明：晶粒越细长，板材的疲劳裂纹扩展速率越快；且随着疲劳裂纹扩展速率的降低，裂纹宽度增加且裂纹路径曲折；稀土元素Er 的加入，在合金中形成Al3(Er,Zr)第二相粒子，其强烈地钉扎位错，阻碍位错运动，以减少位错在晶界处的聚集产生的应力集中，降低板材的疲劳裂纹扩展速率。

Abstract:

The Er-containing Al-Mg alloy plates were processed by different heating treatments. The effects of microstructure on fatigue crack propagation of the plates were analyzed. The results show that, the more slender of the grain, the faster of fatigue crack propagation rate; with the reduction of fatigue crack propagation rate, the crack width increase and crack path twists and turns. Due to the addition of rare earth element Er, formed Al3 (Er, Zr) peticipate particles in the alloy, the Al3 (Er, Zr) pin the dislocation, strongly hinder dislocation motion, in order to reduce the stress concentration in the grain boundary produced by the dislocation pile-up, and then reduce the fatigue crack growth rate.