New role of α phase in the fracture behavior and fracture toughness of a β-type bio-titanium alloy

查看全文 作　　者：Ran [1]Wang;Xiu [1]Song;Lei [1]Wang;Yang [1]Liu;Mitsuo [2,3,4]Niinomi;Deliang [1]Zhang;Jun [5]Cheng 机构地区：[1]Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education)School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;[2]Institute for Materials Research,Tohoku University,2-1-1 Katahira,Aoba-ku,Sendai 980-8577,Japan;[3]Meijo University,1-501 Shiogamaguchi,Tempaku-ku,Nagoya 468-8502,Japan;[4]Nagoya University,Furo-cho,Chikusa-ku,Nagoya 464-8601,Japan;[5]Shaanxi Key Laboratory of Biomedical Metal Materials,Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China 出　　处：《International Journal of Minerals,Metallurgy and Materials》索引2023年第30卷第9期,共8页 基　　金：financially supported by the Natural Science Foundation of Liaoning Province,China (No.2022-MS-113);the Major technology projects of Liaoning Province,China (No.2019JH1/10100004);the National Natural Science Foundation of China (No.52271249);the Key Research and Development Program of Shaanxi,China(No.2023-YBGY-488)。 摘　　要：The role of α precipitates formed during aging in the fracture toughness and fracture behavior of β-type bio-titanium alloy Ti–29Nb–13Ta–4.6Zr(TNTZ) was studied. Results showed that the fracture toughness of the TNTZ alloy aged at 723 K decreases to the minimum of 72.07–73.19 kJ·m^(-2)when the aging time is extended to 4–8 h and then gradually increases and reaches 144.89 kJ·m^(-2)after 72 h. The decrease in fracture toughness within the aging time of 4–8 h is caused by the large stress concentration at the tip of acicular α precipitates with a high aspect ratio and the preferential crack propagation along the inhomogeneous acicular α precipitates distributed in “V-shape” and “nearly perpendicular shape”. When the aging time is extended to 8–72 h, the precrack tip is uniformly blunted, and the crack is effectively deflected by α precipitates with multi long axis directions, more high homogeneity, low aspect ratio, and large number density. Analysis of the effect of αprecipitates on the fracture behavior suggested that the number of long axis directions of α precipitates is the key controlling factor for the fracture behavior and fracture toughness of the TNTZ alloy aged for different times. 关 键 词：fracture toughness Ti-29Nb-13Ta-4.6Zr alloy agedαphase crack tip blunting