陶瓷丸喷丸对2124铝合金疲劳性能的影响

Effect of Ceramic Shot-Peening on Fatigue Behavior of Aluminum Alloy

陶瓷丸硬度大、不易破碎变形,且喷后不易残留在工件表面,是一种新型喷丸介质。为了提高2124铝合金的疲劳性能,对其喷陶瓷丸,并与喷铸钢丸、玻璃丸以及铸钢丸+玻璃丸二次喷丸对比,研究了4种喷丸强化处理的试样的表面形貌、残余应力场分布以及平均旋转弯曲疲劳寿命,分析了喷丸处理影响疲劳性能的机制。结果表明:喷陶瓷丸后铝合金表面残余压应力最大,表面形貌变化不大,疲劳源萌生于喷丸强化的次表层,铝合金疲劳寿命增益最多;喷铸钢丸后,试样表面残余压应力最小,表面形成很深的弹坑而导致强烈应力集中,喷丸对试样疲劳性能的影响不大;玻璃丸和二次喷丸对试样疲劳性能的增益效果居中。

Ceramic shot was adopted for shot-peening of 2124 Al alloy so as to improve the fatigue behavior.The morphology,residue stress distribution and average residue stress of the alloy after shot-peening with ceramic shot,cast-steel shot and glass shot as well as double shot-peening were investigated,and the effect of shot-peening on the fatigue behavior of Al alloy was explored.Results show that the surface compressive residue stress of Al alloy after shot-peening with ceramic shot is the largest,and the surface morphology of the alloy varies slightly.Cracks were initiated beneath the strengthened layer after ceramic shot-peening,and shot-peening with ceramic shot helped to extend the anti-fatigue life of Al alloy most effectively.The Al alloy surface after shot-peening with steel shot had the lowest residue stress,and deep crevices were formed on the surface leading to strong stress concentration.Steel shot-peening had slight effect on the fatigue behavior of the Al alloy.Besides,shot-peening with glass shot and double shot-peening lay in between in terms of the ability to improve the fatigue behavior of the Al alloy.