载荷比对含氢Ti-4Al-2V钛合金疲劳裂纹扩展速率的影响  

Effect of Load Ratio on Fatigue Crack Growth Rate of Hydrogen-Bearing Ti-4Al-2V Titanium Alloy

作　　者：何晓[1] 沈保罗[1] 邱绍宇[2] 邹红[2] 

机构地区：[1]四川大学 [2]中国核动力研究设计院,四川成都610041

出　　处：《稀有金属材料与工程》2004年第9期961-964,共4页Rare Metal Materials and Engineering

摘　　要：研究了含氢量为110g/g和280g/g的Ti-4Al-2V钛合金在不同载荷比下的疲劳裂纹扩展行为。载荷比降低,da/dN曲线向高ΔK方向移动,并逐渐不出现疲劳裂纹的近门槛扩展阶段;无论载荷比和含氢量的高低,稳态裂纹扩展区的裂纹扩展行为符合Paris幂律关系,即da/dN=C(ΔK)m;含氢量为110g/g时,载荷比对稳态裂纹扩展区的da/dN没有影响;含氢280g/g时,载荷比降低,稳态裂纹扩展区的da/dN也降低;载荷比影响裂纹由近门槛扩展区进入稳态裂纹扩展区的应力强度因子范围ΔKp和开始失稳扩展的应力强度因子范围ΔKⅠH。载荷比越小,ΔKp和ΔKⅠH越大。The fatigue crack propagation behavior of the titanium alloy Ti-4Al-2V bearing hydrogen at a concentration of 110 μg/g and 280 μg/g under different load ratios was investigated. Decreasing the load ratio makes the dα/dN curves move to the higher ΔK range and the near-threshold propagation stage gradually disappears. All the curves under different load ratios and hydrogen contents conform to the Paris equation i.e. dα/dN = C(ΔK)m. When hydrogen content is 110 μg/g, the load ratio has little effect on dα/dN in the sub-critical crack growth stage, while for 280 μg/g hydrogen, dα/dN increases with drop of the load ratio. Load ratio affects value of ΔKp(ΔK at point of crack from near-threshold propagation stage to sub-critical propagation stage) and ΔKIH (ΔK at point of crack from sub-critical propagation stage to rapid propagation stage), i.e. ΔKp and ΔKIH increase with the decrease of load ratio.

关 键 词：钛合金 疲劳 氢 载荷比 

分 类 号：TG115[金属学及工艺—物理冶金]