双重退火制度对TC21钛合金断裂韧性的影响

The Effect of Duplex Annealing Heat Treatment on Fracture Toughness of TC21 Titanium Alloy

利用光学显微镜和扫描电镜等手段研究了双重退火工艺对TC21钛合金断裂韧性的影响。结果表明:不同退火制度下TC21钛合金试样断裂韧性均在100MPa·m1/2以上;第一次退火温度相同的条件下,随着第二次退火温度的升高,TC21钛合金断裂韧性都略有升高,而在第二次退火温度相同的条件下,第一次退火温度对TC21钛合金断裂韧性影响较小;经950℃×2h/AC+590℃×4h/AC双重热处理的TC21钛合金具有较崎岖的裂纹扩展路径和较好的塑性,故其断裂韧性最高,可达109.7MPa·m1/2。

In this paper, the effect of duplex annealing process on fracture toughness of TC21 alloy has been re- searched by means of optical microscope and scanning electron microscope. The results show that the fracture tough- ness of specimens under these four duplex annealing processes are all above 100 MPa · m1/2. The fracture toughness of specimens under the second annealing temperature of 590 ℃ are slightly higher than that of specimens under second annealing temperature of 500 ℃ at a given first annealing temperature, but the fracture toughness of specimens at a given second annealing temperature don＇ t change obviously under different first annealing temperatures. The speci- mens under duplex annealing process 950 ℃ × 2 h / AC ＋ 590 ℃ × 4 h/AC can get highest average fracture toughness which can reach 109.7 MPa · m1/2 due to more complicated crack propagation path and better plasticity of specimens under this process.