定向凝固合金DZ17G的高温低周疲劳性能研究

LCF BEHMIOUR OF DS ALLOY DZ17G AT HIGH TEMPERATURE

研究了定向凝固镍基高温合金DZ17G在800℃下的低周疲劳性能，得到其循环应力-应变曲线和应变-寿命曲线，并用最小二乘法回归得到Manson-Coffin方程的数学表达式；对疲劳断口进行了宏观及微观分析，发现裂纹主要在试样内部及近表面缺陷处萌生，裂纹一旦形成即穿晶扩展，且扩展方向垂直于加载轴．

Low cyclic fitigue (LCF) behaviour of a directionally solidified (DS) nickel-base superalloy at high temperature was studied in this paper. Its cyclic stress-strain curve and strain-life curve were obtained. Manson-Coffin equation was obtained through least-square procedure. By macro-and micro-scopy observation, it was discovered that cracks initiated predominantly at interior and near-surface defects. Once formed, cracks propagated transgranularly and normal to the loading direction.