The influence of laser heat treatment on the geometric structure of the surface and condition of the surface layer and selected properties of Waspaloy

Abstract

In the aviation industry the nickel-based superalloys such as Waspaloy are very often used. Conventional machining of this alloys is difficult and expensive. Therefore a Waspaloy requires the new techniques for machining like e.g. Laser Assisted Machining (LAM). New development directions of mechanical engineering are focusing on this type of hybrid machining, where materials are heated and cut in the single process. LAM enables increasing the material machinability through the increase of its temperature in cutting zone. It is assumed that additional increased temperature in the contact zone between surface of material and cutting tool causes the increase of machinability. This paper presents the results of laser heat treatment process on Waspaloy material. The influence of laser heat treatment parameters on the surface condition and selected properties of Waspaloy were analyzed. Laser heat treatment was carried out using diode laser with nominal power equaled to 3.0 kW. The laser beam power density and its scanning laser beam velocity were analyzed. In the first step the single laser tracks were prepared and analyzed. In the second step the multiple laser tracks were prepared. The special attention was directed on change in microstructure. It was found that the laser heat treatment have significant influence on microstructure. The dendritic microstructure of Waspaloy which is characterized by a lower microhardness, causes better machinability of this material.