Influence of laser heat treatment on microstructure and properties of surface layer of Waspaloy aimed for laser-assisted machining

Abstract

In this study, a nickel-based superalloy, Waspaloy, was laser heat treated with diode laser. Single laser tracks were manufactured with different laser beam power densities between 63 and 331 kW/cm 2 , and scanning laser beam speed ranged from 5 to 100 m/min. It was found that laser heat treatment of Waspaloy causes decrease in material hardness-the microhardness in laser tracks is about 300 HV0,1 while the microhardness of substrate is ranged from 300 to 600 HV0,1-which is a positive phenomenon for laserassisted machining of investigated material. Impacts of laser heat treatment parameters on laser tracks properties were identified for obtaining multiple laser tracks with the most homogenous thickness. Moreover, roughness of heated layers was measured to specify surface quality after laser heat treatment. Multiple laser tracks were produced using different scanning laser beam speed and distances between laser tracks ranged from 0.125 to 1 mm. It was found that if scanning laser beam speed is 75 m/min and distance between laser tracks is equal to or lower than 0.25 mm, in microstructures of multiple laser tracks, cracks are occurring. The most suitable laser heat parameters for obtaining heated layers, and which can be used for laser-assisted machining, were identified as laser beam power density 178.3 kW/cm 2 , scanning laser beam speed 5 m/min, and distance between laser tracks 0.125 mm.

Properties of Jet-Plated Ni Coating on Ti Alloy (Ti6Al4V) with Laser Cleaning Pretreatment

“…Methods for improving the surface properties of titanium alloys include electroless plating [4,5], electrodeposition [6], laser cladding [7,8], spray coating [9], air atmosphere treatment [10], laser assisted machining [11,12] and laser heat treatment [13][14][15]. Electrodeposition with a simple process and low cost is commonly used in the preparation of nan materials, composite plating, and special function plating [15,16].…”

Microstructure and selected properties of Monel 400 alloy after laser heat treatment and laser boriding using diode laser

“…Moreover, it was found that addition of copper which is the second main element of Monel 400, to boron layer, reduces brittleness and enhances wear resistance of the surface [5,18]. Borided layers are mostly produced in diffusion processes but in the last two decades of intensive laser techniques progress, there was a much increase in using lasers for obtaining boron-alloyed metal surfaces [14,16,17,[19][20][21][22][23][24] and others [25][26][27][28][29][30][31][32][33][34][35][36].…”

“…In addition, diode lasers are characterized by lower maintenance costs and a possibility to deliver a radiation in fiber. These features resulted in raising interest in using diode lasers for metal processing, for example, laser alloying [19-23, 26, 28, 30-33], laser hardening [24,29,34], or laser-assisted machining [27,[34][35][36]. Because of their potential, diode lasers systems are still improved to obtain better beam quality and higher power intensity [29].…”

“…The second is to determine modifications in microstructure and microhardness changes resulting from laser-alloying Monel 400 with two different contents of boron and four different laser beam scanning velocities. Parameters of laser heat treatment were chosen basing on previous research focusing on laser processing of Waspaloy [34]. Additionally, on the basis of laser heattreated area depth measurements, the influence of boron content on heat conduction through processed material is considered.…”

Microstructure characterisation of Inconel 718 after laser assisted turning

“…The main problem occurs in the correlation of technological parameters on various quality indicators. The improvement of the effects of LAT is related to the area of technological and geometric variable parameters occurring in the cutting process [4][5], laser heating [6][7][8][9] and geometric variables defining the relationship between the place of beam incidence and material decohesion [3,6,9]. Better machinability indicator can be achieved by using two kinematic variations of the laser-assisted machining process: by thermal softening of the heated cutting layer and by changing the microstructure of the surface layer of the workpiece [3].…”