航空用 AF1410 钢的低周疲劳特性及其扩展速率研究

On Low Cycle Fatigue Behavior and Crack Propagation Rate of AF1410 Steel

ＡＦ１４１０超高强度钢是一种抗应力腐蚀和焊接性能较好的新型航空材料。它是一种可能用于损伤容限设计和代替钛合金的超高强度钢。通过对ＡＦ１４１０钢的五种时效处理状态进行试验研究。根据所得的低周疲劳特性数据，计算给出了疲劳裂纹扩展的ｄａ／ｄＮ～ΔＪ曲线，分析了它的特性，并与３００Ｍ钢和ＴＣ４钛合金作了比较。

Superhigh strength steel AF1410 is a type of new aviation steel, which is good for resisting stress corrosion and is not difficult to weld. It looks promising for replacing titanium alloy in damage tolerance design. We need to look more closely into its low cycle fatigue behavior and its crack propagation rate. So we performed low cycle fatigue tests for five different kinds of ageing treatment and labelled the treatments as Ⅰ,Ⅱ,Ⅲ,Ⅳ, and Ⅴ. We used the test results to calculate its crack propagation curve d a /d N ～Δ J . Comparison with titanium alloy TC4 and 300M steel (see Fig.4) shows that: (1) AF1410 steel is somewhat better than TC4 and 300M steel in low cycle fatigue properties; (2) crack propagation rate of AF1410 is smaller than that of TC4; (3) when Δ K10 2 MPa m , the crack propagation rate of AF1410 steel, aged with treatment Ⅳ, is much smaller than those of 300M and TC4.