TITLE:
The Effect of ECAP Deformation Route on Microstructure, Mechanical and Electrochemical Properties of Low CN Fe-20%Cr Alloy
AUTHORS:
Muhammad Rifai, Hiroyuki Miyamoto, Hiroshi Fujiwara
KEYWORDS:
Equal Channel Angular Processing, Grain Boundaries, Anisotropy, Pitting Corrosion, Tafel
JOURNAL NAME:
Materials Sciences and Applications,
Vol.5 No.8,
June
27,
2014
ABSTRACT:
The effect of the deformation route on the microstructure, and the
mechanical and electrochemical properties of low CN Fe-20%Cr alloy by equal
channel angular pressing, have been investigated focusing 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 in three
orthogonal planes. As has been acknowledged, overall grain fragmentation
proceeded most effectively in route Bc. However, the degree of anisotropy of
microstructural development was different among the three deformation routes.
The fractions of the high angle grain boundary and mean grain boundary
misorientation were high and nearly isotropic in route Bc, whereas they were
consi- derably low in one direction and highly anisotropic in routes A and C.
Most importantly, those two parameters were the highest in route C if limited
to the transverse direction (Y-plane), i.e. normal to both the insert and extruding directions. This result contrasted with
FCC materials, which was reported by most papers having the highest fraction of
high angle grain boundary (HAGB) in route Bc. Ultrafine grained structure with
the highest HAGB on Y-plane in route C exhibited the most stabilized corrosion
behavior.