Investigation of mechanical properties on the 3-step T6 treated Al6061/SiCp cascaded bars for structural applications

Abstract

AbstractThis paper investigates the effect of the SiC and triplex thermal aging treatment (TTAT) on the mechanical behavior of compound bars. The bars were fabricated by varying the SiC (2, 4 and 6 wt. %) in Al6061. Initially, bars were tested for hardness and compression strength in homogenized conditions. It is observed that as SiC is increased in the matrix, mechanical properties have improved. The bars with composite cores exhibited better properties as compared to bars with composite casing. For the bar having a composite core, with 2 wt. % SiC, the compression strength was 530.70 MPa, for the 4 wt.% SiC core it was 589.35 MPa and for the 6 wt.% SiC it was 691.88 MPa. Failure was progressive, with noticeable signs of failure, and the load-bearing ability was found to be fairly stable up to nearly 218 kN. Later, the bar with a 6 wt. % SiC core was subjected to TTAT, and surface hardness, compression strength, and interfacial shear strength were found to have increased by 11.2, 3.2 and 11.11%, respectively. SiC are the hard particles; reinforcing them in a soft matrix induces strain in the lattice and thus enhances the hardness of the composite. During aging, the diffusion of alloy atoms is blocked by the generated dislocations present around the SiC particles. Hence, the bars with a higher quantity of SiC in the composite core can be used for high load-bearing structural applications due to their superior mechanical properties as an alternative to the simple composite bars with the same SiC quantity.

Keywords

• Compound bar
• SiC
• triplex aging
• compression
• shear
• Ian Philip Jones, The University of Birmingham, United Kingdom; Manoj Kumar Tiwari Indian Institute of Technology Kharagpur, India