Phase transformation and structural evolution in a Ti-5at.% Al alloy induced by cold-rolling
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2020年第14期
论文作者：Bingqiang Wei Song Ni Yong Liu Xiaozhou Liao Min Song
文章页码：211 - 223
摘 要：The phase transformation, deformation mechanism and their correlation in a cold-rolled Ti-5 at.%Al alloy were investigated. Two types of phase transformations from a hexagonal close-packed（HCP） structure to a face-centered cubic（FCC） structure were observed: the basal-type（B-type） with an orientation relation---ship of < 1210 HCP//< 110 FCC and {0001}HCP//{111}FCC, and the prismatic-type（P-type） with an orientation---relationship of < 1210 HCP//< 110 FCC and 1010 HCP//110 FCC. The two types of transformations both accommodate the strain along the < c> axis of the HCP matrix. With the proceeding of deformation, different deformation mechanisms were activated in the FCC and the HCP structures, respectively, which led to a faster grain refinement rate in the FCC structure than in the HCP matrix. Deformation twins with zero macroscopic strain were prevalent in the FCC domains produced by the B-type transformation, while deformation twins with macroscopic strain were normally observed in the FCC domains produced by the P-type transformation. This is in accordance with the lattice mismatches produced during phase transformation. The easy occurrence of deformation twinning in the FCC structure contributed significantly to the grain refinement process. In addition, the interaction between neighboring FCC domains produced by the two types of phase transformations also accelerated the grain refinement process.
Bingqiang Wei1，Song Ni1，Yong Liu1，Xiaozhou Liao2，Min Song1
1. State Key Laboratory of Powder Metallurgy, Central South University2. School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney
摘 要：The phase transformation, deformation mechanism and their correlation in a cold-rolled Ti-5 at.%Al alloy were investigated. Two types of phase transformations from a hexagonal close-packed（HCP） structure to a face-centered cubic（FCC） structure were observed: the basal-type（B-type） with an orientation relation---ship of < 1210 HCP//< 110 FCC and {0001}HCP//{111}FCC, and the prismatic-type（P-type） with an orientation---relationship of < 1210 HCP//< 110 FCC and 1010 HCP//110 FCC. The two types of transformations both accommodate the strain along the < c> axis of the HCP matrix. With the proceeding of deformation, different deformation mechanisms were activated in the FCC and the HCP structures, respectively, which led to a faster grain refinement rate in the FCC structure than in the HCP matrix. Deformation twins with zero macroscopic strain were prevalent in the FCC domains produced by the B-type transformation, while deformation twins with macroscopic strain were normally observed in the FCC domains produced by the P-type transformation. This is in accordance with the lattice mismatches produced during phase transformation. The easy occurrence of deformation twinning in the FCC structure contributed significantly to the grain refinement process. In addition, the interaction between neighboring FCC domains produced by the two types of phase transformations also accelerated the grain refinement process.
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