TC4-DT钛合金的室温高周疲劳断裂特点  

Room-Temperature High-Cycle Fatigue Fracture Features of TC4-DT Titanium Alloy

作　　者：姜涛 张兵 张仕朝 王新南 JIANG Tao;ZHANG Bing;ZHANG Shichao;WANG Xinnan(AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China;Failure Analysis Center of Aviation Industry Corporation of China,Beijing 100095,China;Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation,Beijing 100095,China;Aviation Key Laboratory of Science and Technology on Materials Testing and Evaluation,Beijing 100095,China;Key Laboratory of Science and Technology on Aeronautical Materials Testing and Evaluation,Aero Engine Corporation of China,Beijing 100095,China)

机构地区：[1]中国航发北京航空材料研究院,北京100095 [2]航空工业失效分析中心,北京100095 [3]航空材料检测与评价北京市重点实验室,北京100095 [4]材料检测与评价航空科技重点实验室,北京100095 [5]中国航空发动机集团材料检测与评价重点实验室,北京100095

出　　处：《机械工程材料》2024年第2期22-29,共8页Materials For Mechanical Engineering

摘　　要：在不同应力比(0.5,-1)下对损伤容限型TC4-DT钛合金进行室温高周疲劳试验,对比分析了不同疲劳寿命下光滑试样与缺口试样的典型断口中的宏微观特征。结果表明:光滑试样疲劳断口整体粗糙,类解理特征不明显,但疲劳条带清晰,裂纹源主要为单源,瞬断区多呈月牙形,均位于断口一侧边缘;应力比为0.5下104周次疲劳寿命的断口中无明显平坦疲劳裂纹扩展区,而相近疲劳寿命的应力比为-1的断口中可见平坦疲劳裂纹扩展区;应力比为0.5的疲劳裂纹主要在次表面或内部萌生,而应力比为-1的裂纹基本在表面萌生。缺口试样疲劳断口整体平坦,可见类解理特征,疲劳条带清晰;裂纹起源于缺口根部,多源;随着疲劳寿命由104周次延长到106周次,瞬断区由内部移向缺口边缘,应力比为-1下的瞬断区呈纺锤形,而应力比为0.5下的瞬断区由椭圆向纺锤形变化,且应力比为0.5下的疲劳裂纹扩展区更为光滑平坦,瞬断区的塑性断裂特征更明显。The damage tolerance type TC4-DT titanium alloy was subjected to room-temperature high-cycle fatigue tests under different stress ratios,and the macro-and micro-features of the typical fracture of smooth specimens and notched specimens with different fatigue lives were comparatively analyzed.The results show that the fatigue fracture of smooth specimens was generally rough,the cleavage characteristics were not obvious,but the fatigue bands were clear.The crack source of smooth specimens was mainly single source.The transient fracture zone of smooth specimens was almost crescent shaped and located on one side edge of the fracture.When the stress ratio was 0.5,there was no obvious flat fatigue crack extension zone of smooth specimens with 104 cycles of fatigue life,while the flat fatigue crack extension zone was observed on the fracture with the similar fatigue life under the stress ratio of-1.The fatigue cracks of smooth specimens were mainly initiated from the subsurface or inside under the stress ratio of 0.5,and were basically initiated from the surface under the stress ratio of-1.The fatigue fracture of notched specimens was generally flat,with cleavage-like characteristics and clear fatigue bands.The cracks of notched specimens were initiated from the notch root and had multiple sources.With the fatigue life extending from 104 cycles to 106 cycles,the transient fracture zone of notched specimens moved from the inside to the edge of the notch.The shape of the transient fracture zone of notched specimens was spindle-shaped under the stress ratio of-1,and changed from ellipse to spindle shape under the stress ratio of 0.5.The fatigue crack extension zone of notched specimens under stress ratio of 0.5 was smoother and flatter,and the characteristics of plastic fracture in the transient fracture zone was more obvious.

关 键 词：钛合金 高周疲劳断裂特征 光滑试样 缺口试样 应力比 

分 类 号：TG146.2[一般工业技术—材料科学与工程]