Severe Plastic Deformation of Pure Magnesium by High Pressure Compressive Reciprocating Shear (HPCRS)

Abstract

Magnesium and its alloys are attractive engineering materials primarily because of their low density of 1.73 g/cc. This makes them significantly lighter than widely used structural metals such as iron, titanium, and aluminium and offer substantial potential for weight reduction. Consequently, magnesium and its alloys find its use as lightweight structural material across several sectors such as automotive, aerospace and consumer electronics. However, many of the applications, predominantly use magnesium in the cast form. However, casting route is limited in its ability to produce thin-walled components (~2 mm or below), which are essential for automotive interiors and a variety of consumer products. In contrast, many of these components could be more readily manufactured using wrought magnesium sheets. Moreover, wrought products also offer higher strength, permitting further weight reduction. However, the use of wrought magnesium products in industry is limited. One of the main reasons is the high cost associated with forming of magnesium due to: 1. Multi-step processing, and 2. The requirement of external heating due low room temperature ductility. To overcome this problem, we introduce a new plastic deformation process to produce wrought magnesium sheets. This process is named High Pressure Compressive Reciprocating Shear (HPCRS). HPCRS can impose large strains and produce magnesium sheets in one step, without external heating. The experiments have been carried out on commercially pure magnesium. The effectiveness of HPCRS in deforming magnesium and achieving fine grain size at different processing parameters is demonstrated, the microstructural evolution as a function of strain and the effect of strain reversal on texture evolution is analysed.