• Yusuf, Shahir Yasin Bin Mohd
• Gao, Nong
• Hoegden, Mathias

Abstract

For the first time, high-pressure torsion (HPT) was applied to additively manufactured AlSi10Mg builtin two directions (vertical and horizontal) by Selective Laser Melting (SLM) and the influence of extreme torsional strain on the porosity, microstructure, and microhardness of the alloy was investigated. ImageJ analysis indicates that significant porosity reduction is achieved by 1/4 HPT revolution (low strain). Optical microscopy (OM) and scanning electron microscopy (SEM) observations reveal the steady distortion and elongation of the melt pools, the continuous elongation of the cellular-dendritic Al matrix, and breakage of the eutectic Si phase network with increased HPT revolutions. Microhardness measurements indicate that despite the significant increase in hardness attained from HPT processing, hardness saturation and microstructural homogeneity are not achieved even after 10 HPT revolutions. X-ray diffraction (XRD) line broadening analysis demonstrates increased dislocation densities with increased HPT revolutions, which contributes to the considerably higher hardness values compared to as-received samples.

Topics

• impedance spectroscopy
• scanning electron microscopy
• x-ray diffraction
• melt
• hardness
• selective laser melting
• dislocation
• porosity
• optical microscopy