TC4钛合金恒定高温和高低温环境下疲劳性能研究  

TC4 Titanium Alloy Fatigue Property at High Temperature and High-Low Temperature Field

作　　者：聂凯 王勇军 NIE Kai;WANG Yongjun(AVIC Chengdu Aircraft Design and Research Institute,Chengdu 610091,China)

机构地区：[1]航空工业成都飞机设计研究所,成都610091

出　　处：《装备环境工程》2024年第6期68-77,共10页Equipment Environmental Engineering

基　　金：“十四五”规划预研项目(403010302)。

摘　　要：目的 研究TC4钛合金在恒定高温和高低温环境(25~390℃)的疲劳性能。方法 分别开展恒定高温和高低温环境的疲劳试验及断口分析,研究材料在2种环境下的疲劳性能差异及温度效应机理。结果 当温度从25℃升高至390℃时,TC4钛合金恒定温度的疲劳性能在短寿命段(N<106循环)逐渐降低,疲劳性能在长寿命段(N>106循环)呈非线性的变化趋势,先降低、后升高。通过断口分析发现,氧化现象随着温度升高和试验时间变长越来越明显。同一应力水平下,高低温环境疲劳试验的疲劳寿命介于最高温度和最低温度疲劳试验的疲劳寿命之间。结论 当温度处于25~390℃时,温度和氧化现象同时影响着TC4钛合金的疲劳性能。温度升高使材料的疲劳性能下降,高温环境生成的保护性氧化膜提高了材料的疲劳性能。钛合金的高低温疲劳寿命可以用等效恒定温度的疲劳曲线来预测,并有较好的预测精度。The work aims to study fatigue property of TC4 titanium alloy at high temperature and high-low temperature field(25-390℃).The difference of fatigue property at two different conditions and the mechanism of temperature effect were studied by high temperature fatigue test,the high-low temperature fatigue test and fractographic analysis.As temperature rose from 25℃to 390℃,the fatigue property of TC4 titanium alloy was reduced in the short life regime(N<106 cycles).The fa-tigue property showed nonlinear variation tendency in the long life regime(N>10^(6) cycles).The fatigue property was enhanced firstly and then showed a degradation tendency.It was observed that oxidation became more and more obvious with the increase of temperature and for the longer test duration as shown in fractographic analysis.At the same stress level,the fatigue life of the high-low temperature fatigue test was longer than that at the highest temperature,and shorter than that at the lowest temperature.When the environment temperature is between 25℃and 390℃,the fatigue property of TC4 titanium is affected by both tem-perature and oxidation at the same time.The fatigue property is degraded with the increase of temperature.On the other hand,the protective oxidation film formed in the high temperature environment can improve fatigue property.The fatigue life at the high-low temperature field can be predicted by a stress-life curve at equivalent temperature.The model has a good predictive precision.

关 键 词：高温 高低温 TC4 钛合金 疲劳性能 氧化 

分 类 号：V252.2[一般工业技术—材料科学与工程]