Achieving enhanced ductility in a dilute magnesium alloy through severe plastic deformation

Abstract

Experiments were conducted to evaluate the utility of a new processing procedure developed for Mg-based alloys in which samples are subjected to a two-step processing route of extrusion followed by equal-channel angular pressing (designated as EX-ECAP). The experiments were conducted using a Mg-0.6 wt pct Zr alloy and, for comparison purposes, samples of pure Mg. It is shown that the potential for successfully using ECAP increases in both materials when adopting the EX-ECAP procedure. For the Mg-Zr alloy, the use of EX-ECAP produces a grain size of ϳ1.4 m when the pressing is undertaken at 573 K. By contrast, using EX-ECAP with pure Mg at 573 K produces a grain size of ϳ26 m. Tensile testing of the Mg-Zr alloy at 523 and 573 K after processing by EX-ECAP revealed the occurrence of significantly enhanced ductilities with maximum elongations of ϳ300 to 400 pct.

Achieving Microstructural Refinement in Magnesium Alloys through Severe Plastic Deformation

“…[11][12][13] However, despite this success there remains a problem that many magnesium alloys fail during processing through the development of substantial cracking or segmentation. This overview examines this problem in section 2 and in section 3 there is a description of some of the advanced properties that may be attained when magnesium alloys are successfully processed by ECAP.…”

3D finite element modeling of grains refinement for magnesium alloys by extrusion-shear and experimental verification

“…The ambient temperature was set as 20°C, and temperature of the ES die is 400°C.The initial billet temperature was chosen to be at a relatively high level 420°C. Heat transfer coefficient between tooling and billet was 11 N/°Cs mm 2 , and the value of heat transfer coefficients between tooling/billet and air are 0.02 N/°Cs mm 2 [11,12] . Emissivity coefficients of the AZ31 and H-13 tool steel were 0.12 and 0.7 respectively.…”

“…But EX-ECAP usually includes more than 2 steps, and the material endures intricate diversification of forming environments including process temperatures and may be oxidized. Matsuyama et al 11 introduced the feasibility of SPD techniques which combines conventional extrusion and equal channel angular pressing into a single process. The extruded material exhibits an excellent balance of strength and tensile ductility.…”

Crack Propagation Analysis of Magnesium Rod Processed by Extrusion-shear: Numerical Modeling and Experimental Verification

“…The EX-ECAP usually includes more than 2 steps, and the material endures intricate diversification of forming environments including process temperature and may be oxidized. Matsubara et al used the EX-ECAP to prepare for the ultrafine magnesium alloy 6,7 , but the ECAP process was only used in the lab scale processing and preparation for nanocrystalline material, there exited an unbridgeable gap between the experimentation and applications of industry.…”