Effect of severe plastic deformation on tensile and fatigue properties of fine-grained magnesium alloy ZK60

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Effect of severe plastic deformation on tensile and fatigue properties of ﬁne-grained magnesium alloy ZK60 Alexei Vinogradova) Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology - NTNU, Trondheim 7491, Norway; and Institute of Advanced Technologies, Togliatti State University, Togliatti 445020, Russia (Received 9 May 2017; accepted 14 June 2017)

Complex wrought magnesium-based alloys suffer from poor ductility, strong yield asymmetry, and lower than desired fatigue performance. These unfavourable properties are exacerbated by the heterogeneity of the microstructure and strong texture forming in Mg alloys during conventional thermo-mechanical processing. For the user, severe plastic deformation (SPD) increases ﬂexibility in tailoring the microstructures and selecting the properties to be emphasized in wrought Mg alloys. The effect of SPD by hot multiaxial forging and equal channel angular pressing on the formation of ﬁne grain microstructure and on resultant mechanical properties is discussed. It is demonstrated that SPD is capable of substantial enhancement in ductility and tensile strength which gives rise to concurrent improvement of both low- and high-cycle fatigue properties. The main message of this overview is that the full potential for improving fatigue performance of Mg alloys can be taken advantage of by way of comprehensive understanding the role of the individual effects associated with the SPD-induced microstructures and textures.

I. INTRODUCTION

In the year of 2000, Mughrabi entered the new ﬁeld of nano-structured and ultra-ﬁne grain (UFG) materials with the highly inﬂuential paper “On the grain-size dependence of metal fatigue: Outlook on the fatigue of ultraﬁne-grained metals”,1 which started a line of enquiry that eventually turned into a long-term program of research in many laboratories worldwide. Based on the wide knowledge about the fatigue behavior of conventional metals and alloys and on the very limited information available about the processing-structureproperties relations of currently emerging UFG materials, he introduced basic concepts that underlined the ﬁeld of research in fatigue of these materials as a whole. He has not only highlighted the most signiﬁcant challenges and opportunities for the anticipated research on the effect of grain reﬁnement by severe plastic deformation (SPD) on fatigue properties but also predicted key trends that

Contributing Editor: Yuntian Zhu a) Address all correspondence to this author. e-mail: [email protected] Dedicated to Professor Dr. Haël Mughrabi on the occasion of his 80th birthday. It is my pleasure and honor to dedicate this paper to Professor Haël Mughrabi, who has been a mentor and a colleague to me over the years, in appreciation of his outstanding contributions and accomplishments in the area of fatigue of advanced materials. DOI: 10.1557/jmr.2017.268

dominated the overall progress in the ﬁeld for years. The speciﬁcally accentuated topics included the inﬂuence of the cyclic slip mod

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