Back stress strengthening and strain hardening in gradient structure. Issue 3 (2nd July 2016)

• Record Type: Journal Article
• Authors: Yang, Muxin; Pan, Yue; Yuan, Fuping; Zhu, Yuntian; Wu, Xiaolei
• Is Part Of: Materials research letters. Volume 4:Issue 3(2016)
• Page Start: 145
• Page End: 151
• Publication Date: 2016-07-02
• Subjects: Back Stress -- Geometrically Necessary Dislocations -- Work Hardening -- Ductility -- Gradient Structure; Materials science -- Research -- Periodicals; Biomedical materials -- Research -- Periodicals; Composite materials -- Research -- Periodicals; Biomedical materials -- Research; Composite materials -- Research; Materials science -- Research; Periodicals; 620.1105
• DOI: 10.1080/21663831.2016.1153004
• Languages: English
• ISSNs: 2166-3831

Abstract

Abstract : We report significant back stress strengthening and strain hardening in gradient structured (GS) interstitial-free (IF) steel. Back stress is long-range stress caused by the pileup of geometrically necessary dislocations (GNDs). A simple equation and a procedure are developed to calculate back stress basing on its formation physics from the tensile unloading–reloading hysteresis loop. The gradient structure has mechanical incompatibility due to its grain size gradient. This induces strain gradient, which needs to be accommodated by GNDs. Back stress not only raises the yield strength but also significantly enhances strain hardening to increase the ductility. Impact Statement: Gradient structure leads to high back stress hardening to increase strength and ductility. A physically sound equation is derived to calculate the back stress from an unloading/reloading hysteresis loop. GRAPHICAL ABSTRACT: