Investigating the Microstructural Evolution and Characterization of Additive Manufactured Zn-Sn-Ti/Ti-6Al-4V Composite.

Abstract

The investigation focused on studying how the reinforcement powders and titanium alloy substrate were influenced by the volumetric energy which was absorbed. The only processing parameters which were varied was the laser intensity and the scanning speed, which were employed to design the direct laser metal deposition (DLMD) single- and multi-tracks. Laser surface modification techniques has unique benefits and properties compared to other conventional techniques. These techniques have process factors that affect directly the microstructure of materials which in turn influence the materials properties. The results revealed dense microstructure in the fabricated coatings in terms of the microstructural evolution, the sizes of the different grains, the structure of the phases formed and the orientation. The modified surface layer of the additively manufactured coating had improved and had a fine microstructure. Optimizing the DLMD processing conditions resulted in a crack-free surface layer but still promoted a few population of gas defects. The micro-hardness measured in the 5Zn-10Sn-Ti coating at 900 W and scan speed of 1.0 m/min was approximated to be 637 HV at all processing conditions employed, and with respect to the hardness of the substrate, there was a 51.33% increase from 310 HV. But increase of 57.2% was noted at 900 W, 1.0 m/min for 5Zn-10Sn-Ti coating. There was enhancement in the results of the micro-hardness tests conducted and this was due to the resulting microstructural evolution. Homogeneous and dense microstructures was accountable for the micro-hardness performance measured.