In-situ investigation into the deformation behavior of Ti-6Al-4V processed by laser powder bed fusion

In this work, we presented an investigation into the deformation behavior of laser powder bed fusion (LPBF) Ti-6Al-4V (Ti64), particularly how microstructure characteristics determined the grain deformation behavior by using in-situ SEM tensile characterization. Results demonstrated that alpha laths with their elongation directions 45 degrees to the tensile loading axis and alpha laths with the larger thickness could induce severe strain accumulation during the uniaxial tensile process. Crystallographic orientations and grain morphologies of alpha lath were considered the key factors that could influence the deformation behavior. The strain localization was observed in the alpha laths dominated by multiple slip systems. Furthermore, the alpha laths with their elongation directions 45 degrees to the tensile loading axis had the longest effective slip length, which could make alpha laths favorable for deformation. The dislocations multiplication of coarse alpha laths was much greater than in fine alpha laths, which could also result in strain localization. These findings could shed light on the deformation behavior related to lamellar structure in LPBF Ti64 and could further help the mechanical property manipulation.

Automated summary

The investigation focused on how microstructure characteristics determined the grain deformation behavior of Ti-6Al-4V in laser powder bed fusion. The orientation, thickness, and elongation direction of alpha laths were found to significantly impact the strain accumulation during uniaxial tensile process. The findings provide insights into deformation behavior related to lamellar structure in LPBF Ti64 and facilitate mechanical property manipulation.