Review

Review on globularization of titanium alloy with lamellar colony

State Key Laboratory of Solidification Processing, Shaanxi Key Laboratory of Precision Forming Technology and Equipment, School of Materials Science and Engineering, Northwestern Polytechnical University, PO Box 542, Xi'an 710072, PR China

^* e-mail: lihongwei@nwpu.edu.cn

Received: 2 February 2020
Accepted: 21 April 2020

Abstract

The globularization of titanium alloy with lamellar colony during hot working is an important way to obtain fine and homogeneous microstructure which has excellent mechanical properties. Because of its great technological importance, globularization has captured wide attention and much research. This paper conducts a systematic study on state of art on globularization of titanium alloy, which mainly includes globularization mechanism, prediction model and the effects of hot-working parameters and microstructure parameters. Firstly, the shortcomings of the well-known globularization mechanisms (dynamic recrystallization, boundary splitting, shearing mechanism and termination migration) were summarized. Moreover, the comparison and analysis of prediction models were accomplished through tabular form. In addition, the effects of hot-working parameters (strain, strain rate, temperature) and microstructure parameters (alpha/beta interface, geometry necessary dislocation and high temperature parent beta phase) were systematically summarized and analyzed. Meanwhile, this study also explores those difficulties and challenges faced by precise control on globularization. Finally, an outlook and development tendency of globularization of titanium alloy are also provided, which includes microstructure evolution of three-dimensional lamellar alpha, the relationship between lamellar colony and mechanical properties and the effect of severe plastic deformation on globularization.