Effect of ECAP Deformation Route on the Degree of Anisotropy of Microstructure of Extremely Low CN Fe-20mass%Cr Alloy

Metals

Muhammad Rifai¹  Hiroyuki Miyamoto² 

[1] Graduate School of Science and Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0394, Japan; E-Mail:;Department of Mechanical Engineering, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0394, Japan; E-Mail:

关键词: EBSD;    steel;    equal-channel angular processing;    grain boundaries;    anisotropy;   

DOI  :  10.3390/met4010055

来源: mdpi

【 摘 要 】

The effect of the deformation route on the microstructural evolution of low CN Fe-20%Cr alloy by ECAP has been investigated, with a focus on the anisotropy of the microstructure. This alloy was pressed at 423 K from one, two and four passes via routes A, Bc and C, and the microstructure was observed three dimensionally. As has been acknowledged, overall grain fragmentation proceeded most effectively in route Bc, and the highest hardness was obtained following routes C and A. However, the degree of anisotropy of microstructural development is different among the three deformation routes. The fractions of the high angle grain boundary (HAGB) and mean grain boundary misorientation were high and nearly isotropic in route Bc, whereas they are considerably low in one direction and highly anisotropic in routes A and C. Most importantly, those two parameters and hardness are the highest in route C if limited to the transverse direction, i.e., normal to both the insert and extruding directions. This result contrasts with FCC materials which most papers report as having the highest fraction of HAGB in route Bc. This result can be interpreted by the slip irreversibility of screw dislocations which is predominant in BCC metals.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.