TC4钛合金的疲劳裂纹扩展Walker公式

为了研究不同应力比下TC4钛合金疲劳裂纹扩展特性,用Warker公式来描述不同应力比下的疲劳裂纹扩展速率.按照标准试验方法,试验加载应力比分别为0.06,0.5,0.7.利用递增多项式数据处理的计算程序,绘制了铸造TC4钛合金疲劳裂纹扩展速率曲线,并对疲劳断口进行扫描分析,计算Walker公式下的材料常数.结果表明,当应力比R≥0时,疲劳裂纹扩展速率随应力比的增大而增大,表现为疲劳条带间距增大.计算得材料常数m为4.082 16,n为-0.023 91,C为6.963 04×10-7.

Walker Formula of Fatigue Crack Propagation of TC4 Titanium Alloy

In order to study fatigue crack propagation characteristics of TC4 titanium alloy under different stress ratios,Warker formula was used to describe the fatigue crack growth rate under the different stress ratios.The fatigue crack propagation rates of TC4 titanium alloy were measured by means of standard test methods.The test load stress ratios were 0.06,0.5 and 0.7.The curves of fatigue crack growth rate of TC4 titanium alloy were plotted with data processing by incremental polynomial calculation program,and fatigue fracture surfaces were analyzed by SEM.The material constants in the formula Walker were calculated.The results showed that fatigue crack propagation rate,namely fatigue strip space,increased,with the increasing of stress ratio,when the stress ratio R was bigger than 0.The material constants m,n and C in the formula Walker were 4.08216,-0.02391 and 6.96304×10-7 respectively.