TY - JOUR
T1 - Effects of microstructure heterogeneity on tensile properties and failure mechanism of GTAW joint of as-cast Ti2531
AU - Gong, Haichao
AU - Fan, Qunbo
AU - Zhang, Hongmei
AU - Wang, Duoduo
AU - Yu, Hong
AU - Yang, Lin
AU - Zhu, Xinjie
AU - Wang, Le
N1 - Publisher Copyright:
© 2022
PY - 2022/12
Y1 - 2022/12
N2 - In this study, as-cast dual-phase titanium alloy Ti2531 was welded by Gas Tungsten Arc Welding, and the effects of microstructure heterogeneity on tensile properties and failure mechanism was analyzed. Tensile test results showed that the specimens fractured in the base metal region, and the tensile strength Rm of the welded plate was 855 MPa ∼ 859 MPa, which was almost the same as that of the base metal. It was found that, compared with the base metal region, the fine and basketweave phase in the weld zone and heat-affected zone resulted in higher hardness and yield strength. Therefore, plastic strain concentration occurred in the base metal region and a large number of kink bands were found, which accounts for the relatively good plasticity with the fracture strain of 0.073–0.09. In addition, by means of intergranular orientation analysis, it was demonstrated that [0001]α and [101]β were the rotation axes of kink bands in the α and β phases, respectively. Furthermore, by observing the high-resolution electron microscopy, it was found that these kink bands were formed by the arrangement of edge dislocations. As a consequence, when the lattice distortion was severe, the unstable expansion of kink bands occurred and cracks were formed in widmanstätten colonies, inducing the failure of the specimen in the base metal region and great tensile strength equivalent to that of base material.
AB - In this study, as-cast dual-phase titanium alloy Ti2531 was welded by Gas Tungsten Arc Welding, and the effects of microstructure heterogeneity on tensile properties and failure mechanism was analyzed. Tensile test results showed that the specimens fractured in the base metal region, and the tensile strength Rm of the welded plate was 855 MPa ∼ 859 MPa, which was almost the same as that of the base metal. It was found that, compared with the base metal region, the fine and basketweave phase in the weld zone and heat-affected zone resulted in higher hardness and yield strength. Therefore, plastic strain concentration occurred in the base metal region and a large number of kink bands were found, which accounts for the relatively good plasticity with the fracture strain of 0.073–0.09. In addition, by means of intergranular orientation analysis, it was demonstrated that [0001]α and [101]β were the rotation axes of kink bands in the α and β phases, respectively. Furthermore, by observing the high-resolution electron microscopy, it was found that these kink bands were formed by the arrangement of edge dislocations. As a consequence, when the lattice distortion was severe, the unstable expansion of kink bands occurred and cracks were formed in widmanstätten colonies, inducing the failure of the specimen in the base metal region and great tensile strength equivalent to that of base material.
KW - As-cast titanium alloy
KW - Failure mechanism
KW - Kink bands
KW - Welding performance
UR - http://www.scopus.com/inward/record.url?scp=85139386803&partnerID=8YFLogxK
U2 - 10.1016/j.matchar.2022.112258
DO - 10.1016/j.matchar.2022.112258
M3 - Article
AN - SCOPUS:85139386803
SN - 1044-5803
VL - 194
JO - Materials Characterization
JF - Materials Characterization
M1 - 112258
ER -