The Evolution of Hardness Homogeneity in Commercially Pure Ti Processed by ECAP

• Published in: Journal of Wuhan University of Technology. Materials science edition 2014-06, Vol.29 (3), p.578-584
• Main Authors: Liu, Xiaoyan, Zhao, Xicheng, Yang, Xirong, Jia, Jiangping, Qi, Boli
• Format: Article
• Language: English
• Subjects: Billets; Chemistry and Materials Science; Cross sections; ECAP; Equal channel angular pressing; Evolution; Hardness; Homogeneity; Materials Science; Microhardness; Planes; 加工; 横截面; 演变; 硬度均匀性; 等通道转角挤压; 纯钛; 表面硬度
• ISSN: 1000-2413; 1993-0437
• DOI: 10.1007/s11595-014-0960-1

The evolution of hardness homogeneity in commercially pure titanium processed by equal channel angular pressing （ECAP） for up to 4 passes following route C at room temperature using a die of 90° was investigated by recording the microhardness on the cross-sectional and longitudinal planes of each billet. The results show that the hardness increases significantly after the first pass although there is a region of lower hardness on the cross-section running in a band near the bottom surface of the billet, and then increases by very small amounts in subsequent passes. With increasing numbers of passes, the lower hardness region near the bottom surface disappears and the microhardness values are distributed homogeneously throughout the cross- sectional and longitudinal planes after 4 passes of ECAP. The microhardness values in the central regions of the billet are slightly lower than those of the top and bottom surfaces. The results show that good homogeneity may be achieved throughout the billets after 4 passes of ECAP following route C.