Mechanical and Microstructural Properties of Multi-Axially Forged LM6 Aluminium Alloy

Abstract

In the present investigation, commercially available light metal aluminium LM6 alloy was processed by Multi-axial forging (MAF) at ambient temperature. MAF was carried out to an equivalent strain in 0.83, 1.66 and 2.4 i.e., 6 passes, 12 passes and 18 passes, respectively. The mechanical properties like tensile test, compression test, hardness and microstructural characterization were studied in processed and unprocessed samples. Ultimate tensile strength (UTS) and ductility improved from 137 to 185 MPa and 3 to 6.2% for as-received to processed samples, respectively. After 18 passes of MAF, the compression strength (CS) has improved from 342 to 530 MPa. Hardness increased as the number of forging passes increases as compared to unprocessed samples. Optical microscopy images were used to study microstructure observations, the average grain size is reduced from 60 to 2 μm for as-received to processed samples, respectively. Strength and hardness increased because of the grain refinement for the processed samples and the introduction of the high amount of dislocation density into the material during the MAF process. Fracture study was conducted by utilizing scanning electron microscopy, dimples on tensile fracture surfaces revealed that ductile mode of fracture.