A superplastic micro-extrusion technology to develop engineered magnesium micro-components

Abstract

Superplastic micro-extrusion (SME) is a state-of-the-art micro-manufacturing technology that produces intricate shape miniaturized components. Magnesium and its alloys (Mg alloys) are potential contenders for the miniaturization industries due to their lightweight and biocompatibility properties. SME is a promising solution to overcome the room temperature ductility/formability concerns in Mg alloys. Therefore, for the first time, the current work proposes superplastic micro-extrusion technology to manufacture high-performance Mg-RE alloy (QE22) based micro-components. The desirable ultrafine grain (UFG) microstructure suitable for superplasticity is synthesized/engineered and further subjected to two modes of superplastic micro-deformation: (1) micro-forward extrusion (MFE) and (2) micro-backward extrusion (MBE) in pre-optimized extrusion conditions. The test results revealed a uniform hardness profile throughout the developed miniaturized micro-pin and micro-cup. Such homogeneous mechanical properties of the developed micro-components can be attributed to the microstructural engineering and high thermal stability of the developed material especially engineered for the current superplastic micro-extrusion processes. Microstructural analysis in all the conditions linked this distinctive characteristic to the activation of grain boundary sliding (GBS) and its accommodative micro-mechanisms. The physics and fundamental science of superplastic microforming in both micro-forward and micro-backward extrusion domain is established for the engineered Mg-RE alloy. Such investigations on understanding the fundamental mechanisms can address the existing challenges in micro-manufacturing industries.