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20 1 2010 10 Vol.20 Special 1 The Chinese Journal of Nonferrous Metals Oct. 2010 1004-0609(2010)S1-s0127-05 Ti-6Al-4V 1 2 2 (1. 710016 2., 710049) 500~1 000 20 Ti-6Al-4V(TC4) TC4 800 TC4 800 TC4 TC4 800 TC4 1 000 TC4 TG146.23 A Effect of thermal cycling temperature on microstructures and mechanical properties of Ti-6Al-4V alloy ZHAO Yong-qing 1, LI Wen-peng 2, WEI Jian-feng 2 (1. Northwest Institute for Nonferrous Metal Research, Xi an 710016, China; 2. School of Materials Science and Engineering, Xi an Jiaotong University, Xi an 710049, China) Abstract: The changes of microstructures and mechanical properties of Ti-6Al-4V alloy after thermal cycling 20 times from 500 to 1 000 were researched. The results show that the strength of Ti-6Al-4V alloy firstly reduces and then increases with the increase of cycling temperature. If the cycling temperature is lower than 800, its plasticity changes less with the temperature. While the temperature is higher than 800, its plasticity decreases fast. The grain size grows fast with increasing temperature. While the temperature is over 800, the lamellar microstructure forms, when the temperature reaches 1 000, the microstructure is almost lamellar one. Key words: Ti-6Al-4V alloy; thermal cycling; mechanical properties; microstructures [1] [2 10] Ti-6Al-4V(TC4) TC4 TC4 TC4 1 TC4 10 mm 500 650 800 900 1 000 20 5 min TC4 (2007CB613807) 029-86266577 E-mail: trc@c-nin.com

s128 2010 10 OLYMPUS GX71 JSM 2700 2 2.1 TC4 1 TC4 1 TC4 800 500 800 TC4 995 MPa 832 MPa 1 065 MPa 948 MPa 800 800 800 ( 15%) 500~800 800 1 000 1.3% 1 Ti-6Al-4V Table 1 Mechanical properties of Ti-6Al-4V alloy after different temperature thermal cycling Temperature/ σ b /MPa σ s /MPa δ/% φ/% 500 1 080 1 000 16.0 42.0 650 1 000 945 15.0 41.0 800 950 820 15.5 42.0 900 955 850 10.0 18.0 1 000 950 845 3.0 1.5 2.2 1 TC4 500 1 000 1 500 ( 1(a) (b)) 800 900 1 TC4 Fig.1 Tensile fractographs of Ti-6Al-4V alloy after different temperatures thermal cycling: (a) 500, macro-image; (b) 500, micro-image; (c) 1 000, maco-image; (d) 1 000, micro-image

20 1 Ti-6Al-4V s129 1 000 TC4 800 800 1 000 ( 1(c) (d)) 800 TC4 800 1 000 TC4 + 2.3 2 TC4 2 500 β α 800 β α 800 β β α 900 β α α α+β α+β α 1 000 α β 50 µm α+β α β SEM 3 3 500 α β α 650 800 α 500 800 β α 650 TC4 1 000 α+β α β 0.5 µm TC4 4 TC4 800 2 TC4 Fig.2 OM images of Ti-6Al-4V alloy after different thermal cycling temperatures: (a) Original structure; (b) 500 ; (c) 900 ; (d) 1 000

s130 2010 10 4 TC4 α β α ( 5) 3 TC4 SEM Fig.3 SEM images of Ti-6Al-4V alloy after different thermal cycling temperatures: (a) 500 ; (b) 1 000 5 Fig.5 Sketch diagram of grain growth 3 1) 500~1 000 TC4 800 TC4 800 TC4 2) TC4 800 TC4 1 000 REFERENCES 4 800 TC4 Fig.4 Morphologies showing grain growth after thermal cycling at 800 [1],. [M]. :, 2008: 169 172. WU Wei-xin, ZHANG Nan. Investigation and analysis for typical fly accident[m]. Beijing: Defense Industry Press, 2008: 169 172. [2]. [J]., 1998, 18(4): 52 60.

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