Process parameters and thermal physical properties of W-Ni-Cu composite fabricated using selective laser melting

To investigate the process and thermal physical performance of W-Ni-Cu manufactured using the Selective Laser Melting (SLM) technique, an experiment of four variables was conducted to study the influence of laser power, scanning speed, length of the scanning line, and overlap rate on the density. Scanning electron microscopy as well as a thermal analyzer, differential scanning calorimeter, and thermal-mechanical analyzer were used to study the microstructure, thermal conductivity, and thermal expansion. The results show that the density of W-Ni-Cu reaches 94.5% with the optimized process. The microstructure is a type of bridging connection, and agglomeration occurs between the W phases and CuNi phase that wraps around the W phase like a network. When the measuring direction is parallel to the processing direction, the thermal conductivity and thermal expansion coefficients are 120.314 0 W/m•K and 7.16×10-6/K, respectively. When the measuring direction is perpendicular to the processing direction, the thermal conductivity and thermal expansion coefficients are 99.257 2 W/m•K and 7.02×10-6/K, respectively. Test pieces form in different directions with different thermal conductivity and thermal expansion coefficients because of the distribution of W in CuNi and the existence of pores. The study shows that the W-Ni-Cu alloy parts exhibiting better performance can be manufactured directly using SLM. © 2019, Science Press. All right reserved.