喷丸强化因素对Ti811合金高温微动疲劳抗力的影响  

The Effect of Shot Peening Factors on Fretting Fatigue Resistance of Ti811 Titanium Alloy at Elevated Temperature

作　　者：张晓化[1] 刘道新[1] 高广睿[1] 

机构地区：[1]西北工业大学,陕西西安710072

出　　处：《稀有金属材料与工程》2005年第12期1985-1989,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(50171054);航空科学基金(01H53066)

摘　　要：探讨了高温下喷丸强化(SP)因素(残余压应力引入、表面粗糙度增大、表面加工硬化等)对Ti811钛合金微动疲劳(FF)抗力的作用规律和机制。结果表明,SP处理可以有效地提高350℃高温下Ti811合金的微动疲劳抗力,但对500℃下FF抗力有不利影响：SP引入的表层残余压应力增加裂纹闭合力,是SP提高350℃高温下钛合金FF抗力最为重要的因素,SP表面加工硬化的作用为次要因素；SP造成的粗糙度增大在350℃和500℃高温下对钛合金的FF抗力呈现出不利的作用,原因是表面机械损伤的影响突出,这种影响与残余压应力的存在状态有关。The effects of the shot peening （SP） factors i.e. compressive residual stress, surface roughness and micro-structure hardening in shot peened surface on fretting fatigue （FF） resistance of Ti811 titanium alloy at elevated temperature were evaluated. The mechanism of SP on FF was investigated. The results show that shot peening treatment improves FF resistance of Ti811 alloy at 350℃, but it decreases FF resistance of the alloy at 500℃. The compressive residual stress is predominant in improving FF resistance of the alloy at 350℃. Compressive residual stress induced by SP arrests the crack into closure and slow growth. Microstructure hardening induced by SP has less effect on FF resistance. Surface roughing induced by SP has bad effect on FF resistance of the alloy at both 350℃ and 500℃ due to shot peening introducing micro-cracks which play important role in FF crack initiation process. The effects of surface roughing on FF resistance rely on compressive residual stress introduced by SP.

关 键 词：钛合金 微动疲劳 喷丸强化 高温 残余应力 

分 类 号：TG113.25[金属学及工艺—物理冶金]