Study On Printing Quality And Mechanical Properties Of Ti-6Al-4V Alloy By Selective Laser Melting

Selective Laser Melting(SLM)is one of the most popular near-net forming methods in recent years.It uses metal powder to directly form metal and has a particularly high material utilisation rate for complex shaped parts.This paper presents a systematic experimental study and theoretical analysis of print defects,surface roughness,micro structure and mechanical properties of Ti-6Al-4V alloys formed by selected laser melting(SLM)using techniques such as metallographic microscopy(OM),scanning electron microscopy(SEM),three-dimensional profile testing,micro hard ness testing and tensile testing.The results show that:(1)Scanning speed has a greater effect on porosity than laser power,and the suitable scanning speed range is wider at high power;(2)Reducing laser power and increasing scanning speed monotonically increases surface roughness;(3)Printing at the same laser energy density,the porosity or density of the alloy is not uniform,but still depends on the specific scanning speed and laser power,but the surface roughness is basically the same;(4)The micro structure of Ti-6Al-4V alloy formed by selected-area laser melting(SLM)is ?' martensitic,which refines with increasing scanning speed and decreasing laser power;(5)Too fast or too slow scanning speed affects the hardness of the alloy,while increasing laser power is beneficial to enhancing the hardness of the alloy;(6)Gradient alloys are prone to fracture at locations with high porosity during stretching.A suitable laser energy density is beneficial to improve the print quality and mechanical properties of the alloy,but the print quality of the same laser energy density alloy still depends on specific process parameters.