Influence of Process Parameters on the Mechanical Properties of Laser Deposited Ti-6Al-4V Alloy. Taguchi and Response Surface Model Approach

Abstract

Titanium alloys have found increased applications in marine, medical, military, aerospace, and automobile industries because of their light weight, good fatigue strength and corrosion-resistance properties. The present study is focused on establishing the effect of process parameters on the coatings performance of Ti-6Al-4V alloy (Grade 5) by optimizing the mechanical properties using Taguchi method and Response Surface Model (RSM). Laser surface alloying was performed using a 3-kW continuous wave (CW) Ytterbium Laser System (YLS) controlled by a KUKA robot which controls the movement of the nozzle head and emitting a Gaussian beam at 1064 nm. The relationships between the input laser-alloying parameters (laser power, scanning speed and powder feed rate) and the process responses (hardness, yield strength and tensile strength) were investigated. The L4 orthogonal array based on design of experiments was used to conduct the experiments. The degree of influence of each process parameter on individual performance characteristic was analyzed from the experimental results obtained using both Taguchi method and RSM. Analysis of variance (ANOVA) demonstrated the significant and non-significant parameters as well as validity of predicted model. The laser power and scanning speed were identified as the most influential process parameters on the mechanical properties of the laser deposited Ti-6Al-4V alloy. The developed model corresponds with the experimental results with error of 0.01 %.