Influence of Powder Flow Rate on Properties of Laser Deposited Titanium Alloy -Ti6Al4V

Abstract

Titanium alloy-Ti6Al4V is an important aerospace alloy with excellent properties but it is classified as difficult to machine material that requires an alternative manufacturing process. Laser metal deposition process is an ideal alternative manufacturing process that can offset most of the problem encountered while processing the alloy using the traditional manufacturing method. Processing parameter play an important role in the resulting properties of material processed using the laser metal deposition process. The key processing parameters that have significant influence in the properties of the processed material in laser metal deposition process include laser power, scanning speed, powder flow rate and gas flow rate. In this study, the effect of powder flow rate on the evolving microstructure and microhardness of Ti6Al4V using the laser metal deposition process is investigated. The laser power, scanning speed and powder flow rate were kept constant while the powder flow rate was varied between 1.44 g/min and 7.2 g/min. The results showed that the microhardness increased as the powder flow rate was increased. The microstructure was found to change from coarse Widmanstatten alpha to coarse martensitic alpha as the powder flow rate was increased. This study is important to know the required powder flow rate to be employed in order to achieve the desired properties during building of new part as well as repair.