Deformation mechanism of cryorolled Fe-36%Ni strip steel

Changsheng Li,Shuai He,Yanlei Song,Jianjun Zheng,Liqing Chen,Y Qin,J Lin,F Vollertsen,S J Yuan,T A Dean

doi:10.1051/matecconf/20152107012

Abstract

The deformation mechanism of cryogenic rolled Fe-36%Ni steel is investigated with rolling strain of e = 0.24–0.92. Experimental results show that both dislocation slip and twinning are activated at cryogenic temperature as strain e = 0.24, and the mean thickness of deformation twins is about 200 nm. When the rolling strain increases to 0.53, the mean thickness of deformation twins reduces to 50 nm and some curved deformation twins exists. As the rolling strain increases to 0.92, the thickness of deformation twins is no longer changed and the micro shear bands exist due to the concentration of work hardening, which suggests that twinning is activated at the early stage of cryogenic rolling (CR) process. It is assumed that more deformation twins will be fragmented by shear bands during the following CR. The dislocation slip becomes the dominated mechanism again during the following deformation. The mechanism of the Fe-36%Ni steel following CR was analyzed quantitatively.

Highlights

Experimental results show that both dislocation slip and twinning are activated at cryogenic temperature as strain = 0.24, and the mean thickness of deformation twins is about 200 nm
Fe-36%Ni steel is similar to Cu with medium stack fault energy (SFE) and face-centered cubic (FCC) structure at the room temperature [7]
As we know that the deformation mechanism is dominated by dislocation slip for medium SFE metal at ambient temperature [8], while SFE will be lower with the decreased temperature, so there may be a significant change on deformation mechanism of Fe-36%Ni steel during cryogenic rolling (CR)

Summary

Introduction

MATEC Web of Conferences papers mentioned above. Fe-36%Ni steel is similar to Cu with medium stack fault energy (SFE) and face-centered cubic (FCC) structure at the room temperature [7]. As we know that the deformation mechanism is dominated by dislocation slip for medium SFE metal at ambient temperature [8], while SFE will be lower with the decreased temperature, so there may be a significant change on deformation mechanism of Fe-36%Ni steel during cryogenic rolling (CR). In order to explore whether CR is an effective way to enhance the mechanical property of Fe-36%Ni steel, it is essential to research the the deformation mechanism of Fe-36%Ni steel during CR. The deformation mechanism of cryorolled Fe-36%Ni steel was investigated

Experimental

Results and discussion

Conclusions