Studies on Large Strain Rolling (LSR) of AZ31 Magnesium Alloy

Abstract

Recently, Severe Plastic Deformation (SPD) techniques are used to fabricate ultra fine-grained (UFG) micro-structures in a number of metals and hence improve the mechanical properties. Large strain rolling (LSR) is one of the SPD techniques in which large amount of deformation is applied in single pass without causing material fail-ure. Magnesium alloys despite having high specific prope-rties, offers low absolute strength properties compared to aluminium. Moreover it has poor workability. Hence the present work explores the possibility of applying success-fully LSR technique for grain refinement of most commerci-ally used wrought Mg alloy AZ31 (Mg-3Al-1Zn). The results indicate that the grain refinement could be effectively achieved through this method. The initial grain size of 40 um is refined to 2-4 um with 80% r eduction. It is also noticed that grain size reduction after 60% is not much appreciable. More edge cracks appear at and above 60% reductions restrict the maximum strain could be applied in a single pass to50-60%. Process parameters like rolling speed, sample preparation etc. are optimized for 60% LSR to minimize the edge cracking problem.