Microstructure and Microhardness Study of Aluminium Graphene Composite Made by Laser Additive Manufacturing

Abstract

Laser additive manufacturing (LAM) is one of the advanced manufacturing technologies capable of manufacturing complex engineering components with superior material properties by layer by layer deposition of material directly from CAD model. Layer-by-layer addition of material empowers LAM in selective deposition of pre-defined composition of material shaping the engineering components making it a feature based design and manufacturing technology. The LAM built components largely depends on LAM processing parameters and the quality of single deposited layer. Hence selection of appropriate processing parameters is one of the mandatory requirements for achieving superior mechanical properties LAM built components. This paper reports the LAM of aluminium/grapheme (Al-G) composite on Al and SS substrate. 2 kW fibre laser based additive manufacturing with 2 mm laser beam diameter at substrate was used to deposit Al-G layers (Al + 1%wt G) at different combinations of laser scanning speed and laser power. Effect of laser power and scanning speed on the quality of deposited layers was investigated oand optimum parametric window was identified. The Optimum range of energy intensity is 50 to 400 J/mm which favours material deposition (< 50P/v - < 400 J/mm). Thus prepared samples were subjected to optical microscopy, scanning electron microscopy and microhardness measurements. A good quality continuous track is observed at 108 J/mm energy intensity and there is very slight change in hardness observed on Al substrate). A significant increase in micro hardness is observed on SS substrate. The maximum value of HV is 463.6 at 0.6 m/min. laser scanning speed and 1.2 kW laser power. These LAM built Aluminium grapheme composite have potential applications in the field of light weight and high strength material for manufacturing of complex shape and cellular structure.