Effect of processing parameters on the properties of laser metal deposited Ti6Al4V using design of experiment

Ti6Al4V is an important aerospace alloy and it is used in some other applications because of its excellent properties. Processing Titanium and its alloys using the conventional manufacturing process is quite challenging. Also, producing a complex part through the conventional manufacturing route involves breaking the part into smaller parts, each part manufactured separately and all the parts later assembled. The assembled part is much heavier because of the additional materials used in joining and fastening the parts together. Laser Metal Deposition (LMD), an additive manufacturing process, can produce complex parts directly from the three Dimensional (3-D) Computer Aided Design (CAD) model of the parts layer by layer in a single manufacturing process. The processing parameters have strong influence on the quality as well as the properties of the parts produced in the LMD process. In this chapter, the powder flow rate and the gas flow rate were varied to study their effect on the physical, metallurgical and mechanical properties of the laser metal deposited Ti6Al4V. The physical properties studied are: the deposit track width and the track height. The mechanical property studied is the Microhardness using Microhardness indenter at a load of 500 g and dwell time of 15 μm. The metallurgical property studied is the microstructure of the laser deposited Ti6Al4V using the Optical microscopy. This study revealed that as the powder flow rate was increased, the track height was increased while the track width was decreased. As the gas flow rate was increased, the deposited track width was found to increase, the track height was initially increased as the gas flow rate was increased then later decreased as the gas flow rate was further increased. The microhardness was found to also initially increase as the powder flow rate was increased and then decreased as the powder flow rate was further increased. As the gas flow rate was increased, the microhardness was increased. © 2014 Taylor & Francis Group, London.