Processability approach for laser powder bed fusion of metallic alloys

Abstract

Processability refers to the ease of achieving the required component while maintaining mechanical performance and processing schedules, which are critical for determining the cost and efficiency of using a given material, from the raw condition to the final product of any manufacturing process. Components built using the laser powder bed fusion with metallic alloys (LPBF-M) process show variability in their mechanical performance, which can be attributed to a range of process parameters and characteristics of the powder material employed by each type of machine. These variations are currently hindering the adoption of this technology at the industrial level. This paper presents a processability approach that could be applied in the LPBF-M to evaluate the possibility of speeding up productivity and minimising the effect on the mechanical properties and relative density and is defined based on the process parameters and powder material characteristics that generate the melting pool and meet bonding criteria at a specific build rate. A case study is carried out with stainless steel 316 (SS316), although this processability analysis could be applied to any other alloy. The results show that a wide range of process parameters generates a suitable processability interval with different values of the build rate. It is also found that slow build rates give rise to less variability in the mechanical properties, while faster rates produce more variability; this is caused by a fast-growing melt pool due to the use of high scan velocities for the SS316 alloy under study.