Numerical simulation of temperature field distribution for laser sintering graphene reinforced nickel matrix nanocomposites

摘要

Transient temperature field distribution is important for quality control of laser sintering graphene (Gr) reinforced nickel matrix (Ni-Gr) nanocomposites and the optimization of sintering parameters. To date, it is difficult to measure the temperature field directly. Thus, numerical simulation was utilized to study the distribution and evolution of temperature field. Finite element models were employed to simulate the sintering process of Ni-Gr coatings on AISI 4140 steel. The temperature distribution, the depth of the melting pool, the width of metallurgical bonding and the parameter optimizing method for laser sintering were investigated. In order to verify simulation results, single-track experiments were performed with the same laser sintering parameters as simulation. Simulated results reveal that convection and radiation heat transfer, and the latent heat of phase transition play a major role in the sintering process. Simulation output is consistent with experiments under the same processing parameters. Based on simulation results, substrate melting depth, metallurgical bonding width and thermal accumulation effects can be predicted. Thus, according to these guidelines, the optimal laser sintering parameters can be decided. (C) 2016 Elsevier B.V. All rights reserved.