Product Code: ICAL07_1708

A Study of Optimal Laser Parameters by ANOVA Method in Laser Surface Alloyed NiTi with Mo
Authors:
H.C. Man, The Hong Kong Polytechnic University; Kowloon Hong Kong
Ng Ka Wai, The Hong Kong Polytechnic University; Shatin Hong Kong
T.M. Yue, The Hong Kong Polytechnic University; Kowloon Hong Kong
Presented at ICALEO 2007

The present work investigates the influence of process parameters for laser surface alloying with molybdenum on Nickel Titanium, which is extensively used in medical devices industries. A systematic study of process parameters such as laser power, scanning velocity and pre-paste thickness upon the Mo concentration was carried out. Analysis of variance (ANOVA) was used to understand the significance of the process variables affecting the process factors. A functional relationship between the melt profile, structure and micro hardness was identified after a detailed analysis of the variables involved. Laser power and scan speed are found to be most significant process parameters influencing the melt depth. The weight % of Mo and of Ni are directly and inversely proportional to the dilution ratio (DR) respectively. A favorable hardness value can be achieved by an attainable Mo content. With a set of optimal parameters, Mo alloyed layer with hardness three times the substrate NiTi was achieved.