Assessment of microstructural evolution and associated tensile behavior in thin-walled Ti6Al4V parts manufactured via selective laser melting

Abstract

Thin-walled structures plays an important role in the production of lightweight complexity components. Currently, the systematic research works on additive manufacturing of thin-walled components are rarely reported, making it impossible to properly supervise the production of complicated thin-walled parts. The aim of present study was to investigate the effects of thickness on the microstructure and mechanical characteristics of thin-walled Ti6Al4V alloy produced by SLM. As the thickness increased from 0.5 mm to 2.0 mm, surface roughness decreased from 15.702 μm to 5.769 μm, ultimate tensile strength grew from 1052 MPa to 1313 MPa while elongation initially increased and then decreased (all <8%). The microstructure, which has a hierarchical structure with tensile twins, dislocations (dislocation loops), and stacking faults, is dominated by martensite. • The grain size of acicular martensite has an obvious hierarchical structure. • The size effect of “smaller, weaker”. • With the increase of thickness, the surface roughness decreases.