Effect of high-pressure torsion on grain refinement, strength enhancement and uniform ductility of EZ magnesium alloy

• Published in: Materials letters Vol. 212; pp. 323 - 326
• Main Authors: Bryła, Krzysztof, Morgiel, Jerzy, Faryna, Marek, Edalati, Kaveh, Horita, Zenji
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2018; Elsevier BV
• Subjects: Alloys; Ductility; Elongation; Grain refinement; Grain size; Grain size distribution; High-pressure torsion; Magnesium; Magnesium alloys; Magnesium base alloys; Materials science; Pressure effects; Tensile strength; Torsion; Ultimate tensile strength; Ultrafine-grained materials; Ultrafines; Zinc; Ultrafine-grained materials; Magnesium alloys; Grain refinement; High-pressure torsion
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2017.10.113

•Enhancement of tensile strength and uniform ductility of the EZ magnesium alloy was obtained by HPT.•The highest values of tensile strength and uniform ductility were achieved after 3 HPT turns.•Mechanical properties were improved by grain refinement and fragmentation of intermetallic phase. Strength enhancement of Mg-based alloys without deteriorating their ductility is currently a major scientific and industrial challenge. In this study, discs of as-cast EZ33A alloy were processed by high-pressure torsion (HPT). The coarse-grained cast material was turned to ultrafine-grained (UFG) of ∼240 nm, ∼135 nm and ∼127 nm size, after 1, 3 and 10 turns, respectively. Simultaneously, hardness increased from 60 HV for the as-cast material to 90–95 HV after HPT processing. Samples subjected to various HPT routes showed enhanced ultimate tensile strength of 270 MPa, along with their uniform elongation up to 10%. The simultaneous increase of strength and ductility was attributed to the bimodal grain size distribution, as well as to the fragmentation and redistribution of brittle (Mg,Zn)12Ce phase.