Numerical Simulation on Pulsed Laser Ablation of the Single-Crystal Superalloy Considering Material Moving Front and Effect of Comprehensive Heat Dissipation

Abstract

In the present research, an iterative numerical model is proposed to investigate the nanosecond pulsed laser ablation (PLA) mechanism of the DD6 single-crystal superalloy. In the numerical model, two subroutines are introduced to trace the moving boundary and update the thermal load. The iteration between the main governing equation and the two subroutines enables the PLA numerical simulation to consider material moving front and effect of comprehensive heat dissipation including thermal convection and radiation. The basic experimental results exhibit a good agreement with simulation results which indicates the good accuracy of the simulation model. Therefore, the PLA mechanism of the DD6 single-crystal superalloy is studied base on the improved iterative model, which indicates the evolution of temperature field, ablation zone morphology, formation of recast layer and heat-affected zone are closely related with time. The temperature of the laser spot center increases sharply at the first stage, reaching a maximum value of 5252 K, and then decreases gradually. The thermal dissipation postpones the ablation rate but promotes the formation of a recast layer and heat-affected zone. Due to the evaporation and thermal dissipation, the depth of the molten layer exhibits two rapid increasing stages. The comprehensive analysis of the PLA processing by the improved simulation model helps the understanding of the intrinsic mechanism, which would contribute to the further optimizing parameters of PLA fabrication of the DD6 single-crystal superalloy.

Application of a Finite Element Model to Obtain the Influence of the Treatment’s Power, Reflecion and Focal Diameter in Laser Texturing of Aluminum

“…The processed material is pure aluminum having the material characteristics given in Table 1. The liquid and gaseous phase changes are modeled by introducing latent heat (8), which allows the specific heat capacity to be set as constant. It is assumed that the initial temperature of the test specimen is 20 °C.…”

“…Laser texturing is applicable to various materials, such as metals and their alloys, superalloys [8], ceramics [3], wood [9], composite materials [10] and others. Due to its wide application in industry, aluminum and its alloys are the subject of increased research, including regarding the possibilities of its laser processing [11].…”

“…Nikolidakis et al [16] also consider the influence of the evaporated plasma layer. Some authors consider radiation and convection [19], [8], but the process is fast and the heat conduction in the solid body has a dominant effect. Some authors model the liquid phase by solving the Navier-Stokes equations [20].…”

Investigation of Al-Si-Cu-Zn-Y-Base Alloy Powders Prepared by Ultrasonic Gas Atomization for Brazing of an Al-Base Alloy

“…According to the recent findings [34][35][36], the alloying content and solidification condition could exert a strong effect on the microstructure and mechanical properties of the eutectic alloy. In the present research, the nucleation of a-Al would be the first step during the equilibrium solidification of the Al-10Si based alloy and the dendritic or eutectic structure would grow subsequently.…”

Simulation of Laser-Heating and Energetic Plasma Plume Expansion in Pulsed Laser Deposition of Y3Fe5O12

“…Interaction between the laser and the target material, which results in evaporation on the target surface [13][14][15][16][17][18], 2.…”