The finishing experiments of TC4 titanium alloy specimens based on an orthogonal experimental method were carried out using a horizontal centrifugal mass finishing process.The influence of main process parameters on surface roughness,micro-hardness and residual stress were studied,and the optimal process parameters were determined.The mechanism of fatigue resistance improvement was revealed by fatigue test,SEM and XRD diffraction.Results show that the diameter of the media is the most important factor affecting the surface roughness and residual stress.For the one-sided,the surface roughness values,Ra and Rz,decrease maximally by 0.389 μm and 2.353 μm,respectively.The micro-hardness increases from 314 HV0.5 to 367 HV0.5,and the maximum residual compressive stress increases to 308 MPa.While for the double-sided,the maximum decrease of Ra and Rz is 0.356 μm and 2.151 μm,respectively.The micro-hardness increases to 346 HV0.5,and the maximum residual compressive stress increases to 352 MPa.By mass finishing,the fatigue performance can be obviously improved for inhibiting nucleation and expansion of fatigue crack.The fatigue limit of the specimens increases from 389 MPa to 450 MPa with an increase ratio of 15.7％ for one-sided,which increases to 578 MPa with an increase ratio of 48.5％ for the double-sided.%基于正交试验方法,采用卧式离心式滚磨光整加工工艺对钛合金TC4试件进行加工,研究主要工艺参数对表面粗糙度、显微硬度和残余应力的影响,确定了较优工艺参数;通过疲劳试验和SEM、XRD衍射测试等方法,分析了提高抗疲劳性能的效果和机理.结果表明:滚抛磨块直径是影响表面粗糙度值和残余应力的最主要因素;单面加工时,表面粗糙度Ra、Rz最大下降值为0.389 μn和2.353μm,显微硬度可从314 HV0.5增加到367 HV0.5,产生了308MPa的残余压应力;双面加工时,Ra、Rz最大下降值为0.356 μm和2.151 μm,显微硬度增加到346 HV0.5,产生了352 MPa的残余压应力.滚磨光整加工后,表面粗糙度的改善和残余应力的存在,有助于阻碍疲劳裂纹的形成和扩展,疲劳性能明显改善,单面加工可使试件的疲劳极限从389 MPa提高到450 MPa,提高了15.7％,双面加工时提高到578 MPa,提高了48.5％.
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