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| Evolution of Oxygen-Rich Layer and Its Effect on Fatigue Property of Ti-6Al-4V |
| LIU Yunxi1,2,3, CHEN Wei1, LIU Jie4, LI Zhiqiang1,2,3, YAO Gang1, HAN Xiuquan1,2,3 |
(1. AVIC Manufacturing Technology Institute, Beijing 100024, China;
2. Aeronautical Key Laboratory for Plastic Forming Technologies, Beijing 100024, China;
3. Beijing Key Laboratory of Digital Plasticity Forming Technology and Equipment, Beijing 100024, China;
4. The Military Representative of PLA Air Force in North China, Beijing 100013, China) |
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Abstract The microstructure and microhardness of Ti-6Al-4V α-case which experiences thermal exposure at 900℃ , 930℃ and 960℃ are investigated. After thermal exposure of 0.5-24h, the volume fraction of α is much higher in α-case than in sample interior, and the grains grow larger comparing with the original material. The α-case thickness increases with time and temperature increasing. Due to the strengthening effect of oxygen, the microhardness of α-case thickness also increases. The microhardness value decreases from the surface to the interior of the sample, and it becomes stable below 200μm. The α-case on the fatigue sample induces a multi-site fatigue crack initiation mode, which leads to a significant deterioration of fatigue life.
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2018, 
