Enhancing Surface Integrity of Selective Laser Melted Al-Si Alloys through Ultrasonic Assisted Magnetic Abrasive Finishing utilizing SiC Abrasives

Surface finish significantly affects assembled component's functional aspects like fatigue life, corrosion resistance, wear, etc. Ultrasonic-Assisted Magnetic Abrasive Finishing (UAMAF) is an integration of ultrasonic vibrations to Magnetic Abrasive Finishing (MAF) process to finish surfaces up to nanometre level in a short time. Current work focuses on fabricating UAMAF setup on vertical milling machine and finishing Selective Laser Melting (SLM) built samples made of AlSi12Mg alloy using loose Silicon carbide abrasive particles. Finishing was performed on As-built, surface ground samples in which surface roughness reduction percentage was 97.93% in Heat Treated (HT) samples combined with grinding process and UAMAF, 96.57% in Non Heat Treated (NHT) samples combined with grinding process and UAMAF. There was no change in elemental composition even after employing UAMAF. Microstructure showed increase in abrasives impacted on the surface, achieving surface finish in lower time. Magnitude of residual stresses induced during SLM and grinding process reduced drastically by about 112.13%, 149.90% respectively by UAMAF in NHT, HT samples and nature of stresses were altered from tensile to compressive. Overall results revealed that UAMAF is more effective when applied to SLM-printed heat-treated AlSi12Mg samples than cast, non-heat-treated samples. The friable nature of Silicon carbide abrasives influences finishing time which in turn affects surface finish in UAMAF.