摘要
为研究超声深滚处理技术(Ultrasonic Deep Rolling,UDR)对零件表面损伤的抗疲劳修复与强化作用,制备了Ti-6Al-4V缺口疲劳试件,采用UDR技术对缺口疲劳试件进行了深滚强化处理。通过疲劳试验对比了深滚处理前后的缺口试件的抗疲劳性能。采用体视显微镜对疲劳断口和深滚处理后缺口附近的塑性变形进行了观察分析,根据名义应力法和局部应力应变法对缺口件的疲劳寿命进行了计算,并与试验结果进行了比较。结果表明:试验结果与计算结果较接近;与未经超声深滚处理的试件相比,经超声深滚处理后缺口试件的疲劳强度由276 MPa提高到523 MPa。断口分析表明:经超声深滚处理后疲劳裂纹源下移到缺口根部以下0.68 mm处,说明超声深滚在缺口根部引入的残余压应力是提高缺口试件疲劳强度的主要原因。
Notched Ti-6Al-4V fatigue test specimens are prepared and treated by Ultrasonic Deep Rolling (UDR)to investigate the effects of anti-fatigue enhancement and repair of surface damaged parts.Anti-fatigue performance of the UDR treated notched specimens and that of the notched specimens without UDR treatment are compared via fatigue test.Fatigue cracks and plastic deformation near the notch are observed and analyzed using a stereomicroscope.Fatigue strength of the notched specimen is evaluated according to the stress-life approach and the local stress-strain approach and is compared with that ob-tained from fatigue test.Results show that,the tested and evaluated fatigue strength is close to each oth-er.Compared with the untreated notched specimens,the fatigue strength of the notched specimens treated by UDR is increased from 276 MPa to 523 MPa.Fractography analysis shows that the fatigue crack initia-tion site moves to about 0.68 mm under the bottom of the notch,which indicates that it is the compressive residual stress produced by the UDR process that results in fatigue enhancement of the notched specimens.
出处
《装甲兵工程学院学报》
2014年第5期82-86,共5页
Journal of Academy of Armored Force Engineering
基金
军队科研计划项目
