Thermal Model and Numerical Simulation of Selective Laser Alloying Process of Elemental Ti and B

Abstract

TiB2 has excellent performances in terms of wear resistance and corrosion resistance, mechanical strength, high elastic modulus and high compressive strength, hardness, but its application is still limited due to its poor manufacturability. It is expected to provide a transforming technology for its application by implementing additive manufacture of TiB2. The main content of this paper is to propose an innovative technology, selective laser alloying (SLA), using elemental powders of Titanium and Boron provides a transforming technology for the application of TiB2 by enabling its 3D forming from a pure simulation perspective. In this paper, a model of the in-situ reaction process is proposed. By considering the concentration distribution of Ti, B and TiB2, the effects of chemical reaction rate and laser power on the evolution of the free solid–liquid interface and species transport are discussed. The laser energy consumed in the SLA process and the energy released by the chemical reaction were theoretically derived. It showed that the heat released from the exothermic reaction between Titanium and Boron is an important energy source which can reduce the energy input and help improve the manufacturing efficiency of the SLA process; the chemical reaction rate has a significant influence on the concentration distribution of Ti, B and TiB2; the volume and existence time of molten pool and the heat source of reaction strongly relies on the chemical reaction rate and the laser power.