Cyclic Response of SUS316L Stainless Steel Processed by ECAP

Abstract

The cyclic response of the SUS316L stainless steel with the nanostructure induced by profuse twinning during equal channel angular pressing (ECAP) at 423 K was investigated with the focus on the shape of the hysteresis loops and their evolution with cycling. The SUS316L steel with the nanostructured twins showed a very high stress amplitude if compared to their conventional counterparts. However, unlike the as-quenched specimens, the ECAPed SUS316L steel revealed considerable cyclic softening at plastic strain amplitudes above 2 © 10 ¹4 . Besides, the ECAPed specimens showed characteristic stress asymmetry behavior during fatigue. At the initial stages of the fatigue tests, a tensile peak stress of the hysteresis loop was higher than a compressive one. Then, the tensile peak stresses gradually decreased with increasing cycles and finally became lower than the compressive peak stress under plastic strain amplitudes higher than 2 © 10 ¹4. Since no stress asymmetry was detected for the as-quenched sample, the observed stress asymmetry behavior was attributed to the specific asymmetric response of the directionally sheared microstructure created during ECAP.

Fatigue Behavior of Multi-Directionally Forged Commercial Purity Grade 2 Ti Plate in Laboratory Air and Ringer’s Solution

“…The SPD methods were developing for wide range of alloys and pure metals such as copper, 11) magnesium, 12) aluminum, 13) titanium 7,8) and steels. 9,10) The strengthening mechanism is basically attributed to ultrafine-grained (UFGed) microstructures induced by the SPDs. Multi-directional forging (MDFing) process is one of the SPD methods, in which materials are forged with changing forging axes for 90 degrees pass by pass.…”

Effect of Grain Size on Fatigue Behavior in AZ61 Mg Alloys Fabricated by MDFing

“…However, rather large components could be fabricated only by MDF, and that is one of the advantages of MDFing. To use UFGed materials for mechanical components, understanding of their fatigue behavior is very important indeed [10][11][12][13][14] . Consequently, the fatigue strengths of ECAPed Mg alloys have been investigated [11][12][13][14] .…”