Study On Properties Of Inconel 625 Alloy Powder And Products In Selective Laser Melting

As one of the typical technologies of Additive Manufacturing with better economic benefit and broad application prospects, selective Laser Melting(SLM) can produce good performance of complex mechanical metal parts. The study on SLM at home and abroad focuse mainly on the SLM processing parameters, and there is less study on preparation and properties of metal powder in the SLM. In this article, the preparation and properties of Inconel 625 alloy powder were researched, then microstructures and mechanical properties of Inconel 625 alloy products in SLM experiments were analysed, mainly completed the following work:Electrod Inert Gas Atomization(EIGA) technology was used to prepare Inconel625 alloy powder. With Ar atomizing medium, atomization pressure was 3.5 MPa, electrode feed speed was 30 mm/min, the particle surface of Inconel 625 alloy powder was smooth, the particle spherical degree was high, and O content was lower than 0.01%. Mesh sieving and air classification were used to get Inconel 625 alloy powder with the particle size distribution about 15 ~ 53 microns, and it was inevitable that satellite powder and agglomeration phenomenon caused by tiny particles.Laser particle size analyzer, scanning electron microscope and powder performance tester were used to analysis the Inconel 625 alloy powder prepared in this article and imported from abroad. The results showed that the non-metallic of composition in Inconel 625 alloy powder was controlled in the lower levels. The average sphericity of particle was more than 0.8 and there were satellite and hollow ball in powder. The internal microstructures of powder were cellular and dendritic crystal. The particle size range was less than 80 microns, and the average particle size was between 28~35 microns. The particle size distribution interval of 20~30 microns accounted for the most powder. The powder BET specific surface area was less than 0.1 m2/g, hall flow velocity was less than 20 s and the apparent density was more than 4.0 g/cm3. Compared with imported from abroad, the Inconel 625 alloy powder prepared in this article had lower oxygen content, and greater average particle size, so its flow performance and SLM formability were better than the imported powder.The SLM experiment was proceeded on the EOS M280 system using Inconel 625 alloy powder prepared in this article and imported from abroad. The results showed that there was deformation and cracking in the microstructures of Inconel 625 products in SLM equipments. Its surface was concave and convex structure with laser scanning traces. There were micro cracks with the length less than 150 microns and inclusions with the size less than 20 microns in the SLM products of individual imported powder. Its microstructure was a single austenite phase. The density of products reached more than 99% and its brinell hardness was between 270~300. With the yield strength was 690~750 MPa and the tensile strength was 950~1050 MPa, the tensile strength were higher than standard requirements. The fracture of tensile and impact presented ductile fracture characteristics. After 1140?, 2 hours of solution treatment, its hardness falled by 30% while the plasticity and impact energy had been improved in different degrees. The products manufactured by the Inconel 625 alloy powder in this article had uniform microstructure, no micro cracks and inclusions, so its mechanical properties was superior to the products manufactured by the imported Inconel 625 alloy powder.