摘要
目的探究钛合金TC4低周疲劳试样加工过程中残余应力的变化及残余应力对低周疲劳寿命的影响。方法采用X射线衍射法分别对车、磨、抛后的试样进行表面残余应力的表征,分析加工工艺对其的影响,利用液压伺服万能试验机进行低周疲劳试验,分析其表面残余应力对寿命的影响。结果经过粗车、精车、磨削、纵抛,试样加工表面的残余应力不断减小;车削加工参数对试样表面残余应力影响大小为进给速度>转速>单位进刀量;改变磨削工艺参数可以控制试样表面残余应力的变化趋势;纵抛可以改变试样表面的纹路状态,表面残余应力与磨后保持一致。结论根据疲劳试验结果,试样表面残余压应力会提高材料疲劳寿命,但高于230 MPa后,疲劳寿命有明显的降低。表面残余压应力一定程度上会增加材料的疲劳寿命,但当其超过一定值后,会对疲劳低周试验产生危害。
The work aims to investigate the change of residual stress during machining and the effects of residual stress on the low-cycle fatigue life of titanium alloy TC4 samples.X-ray diffraction method was used to characterize the residual stress on the surface of the sample after turning,grinding and polishing,and analyze the effects of processing technology on them.Low cycle fatigue test was conducted on the hydraulic servo universal testing machine to analyze the effects of the residual stress on the life of the sample.The results showed that the residual stress on the machined surface decreased after roughing,finishing,grinding and polishing.The effects of turning parameters on the residual stress on the sample surface were in the order of feed speed>rotational speed>unit feed quantity.Changing the grinding process parameters can control the variation trend of residual stress on the surface of the sample.Longitudinal casting can change the grain state of the sample surface,but the surface residual stress was at the same level as after grinding.According to the fatigue test results,the residual compressive stress on the sample surface can improve the fatigue life of the material,but when it is higher than 230 MPa,the fatigue life is obviously reduced.Surface residual compressive stress will increase the fatigue life of materials to a certain extent,but when it exceeds a certain value,it will cause harm to fatigue low-cycle test.
作者
李志龙
高怡斐
马亚鑫
张志玮
LI Zhi-long;GAO Yi-fei;MA Ya-xin;ZHANG Zhi-wei(Central Iron and Steel Research Institute,Beijing 100081,China;NCS Testing Technology Co.,Ltd.,Beijing 100081,China;Chengdu Aeronautic Polytechnic,Chengdu 610100,China)
出处
《精密成形工程》
北大核心
2022年第3期133-140,共8页
Journal of Netshape Forming Engineering
基金
国家新材料测试评价平台钢铁行业中心开放课题(ZNCS193-2020)。
关键词
X射线衍射法
正交试验
车削
磨削
抛
低周疲劳
X-ray diffraction method
orthogonal test
turning
grinding
polishing
low cycle fatigue
