热疲劳试验后K465合金低压涡轮叶片的组织及性能  

Microstructure and Properties of Low-pressure Turbine Blade of K465 Alloy after Thermal Fatigue Test

作　　者：周中波 杨明波[1] 张建中 时来鑫 Zhou Zhongbo;Yang Mingbo;Zhang Jianzhong;Shi Laixin(Materials Science and Engineering College,Chongqing University of Technology;Chongqing Sannai Technology Co.,Ltd.)

机构地区：[1]重庆理工大学材料科学与工程学院,重庆400054 [2]重庆三耐科技有限责任公司

出　　处：《特种铸造及有色合金》2022年第7期921-924,共4页Special Casting & Nonferrous Alloys

摘　　要：对某航空发动机K465合金低压涡轮叶片在900℃及950℃进行100次冷热循环试验,研究了叶片在热疲劳试验过程中的裂纹萌生及扩展,分析了热疲劳试验后叶片的微观组织及力学性能。结果表明,热疲劳裂纹首先从叶片工艺孔处萌生,垂直于叶片轴向方向扩展,工艺孔及缩松处的应力集中是热疲劳裂纹萌生的主要原因;冷热循环试验后枝晶干γ′相尺寸增大,立方形态γ′相边角变得圆滑不规则,且由于针状二次析出相的析出,叶片的伸长率大幅下降。Through the test at 900 ℃ and 950 ℃ for 100 cooling/heating cycles on the low-pressure turbine blade of K465 alloy an aeroengine, the crack initiation and propagation of the blade during the thermal fatigue test were investigated, and the microstructure and mechanical properties of the blade after thermal fatigue test were analyzed. The results indicate that the thermal fatigue crack is firstly originated from the process hole of the blade and extends perpendicularly to the axial direction of the blade. The stress concentration on the process hole and shrinkage is the main reason for the thermal fatigue crack initiation. After the cooling/heating cycle test, the dimension of γ′ phase in the dendrite arm is increased, and the edges and corners of cubic γ′ phase become smooth and irregular. Due to the precipitation of accicular secondary phase, the elongation of blade is decreased significantly.

关 键 词：K465合金 热疲劳 裂纹 组织 性能 

分 类 号：V232.4[航空宇航科学与技术—航空宇航推进理论与工程]