Abstract
Friction stir processing (FSP) is one of the innovative methods for surface hardening commercial aluminum alloys. It modifies the surface of the alloy in the solid phase state by severe plastic deformation at elevated temperatures. However, most alloys have low thermal stability of the microstructure after FSP. In some cases, abnormal grain growth occurs after high-temperature heat treatment. This study demonstrates the potential to enhance thermal stability of AV (avial, Al-Mg-Si) aluminum alloy microstructure via local surface alloying with high-strength SiC particles by means of FSP and T6 heat treatment. Experimental trials determined the optimal FSP settings for commercial aluminum alloys (rotation speed 1000 rpm, feed rate 16 mm/min) and T6 heat treatment (consisting of solid solution treatment and artificial aging) on AK12D (Al-Si) aluminum alloy. Advanced techniques in optical metallography, scanning electron microscopy, and orientation microscopy (EBSD analysis) were utilized to examine microstructures. The study compared two structural states, AV and AV-SiC alloys, after FSP and T6 heat treatments. The analysis revealed that FSP resulted in the formation of a basin-shaped stir zone whose boundaries extended uniformly to the workpiece surface. FSP has been found to result in the fragmentation and uniform distribution of primary intermetallic phase particles. Additionally, FSP has been shown to contribute to the crushing of SiC particles and their non-uniform distribution in the stir zone. The introduction of highstrength particles into the AV alloy during FSP has also been found to increase its thermal stability. Following a hardening heat treatment, a fine-grained microstructure with an average grain size of about 1.60±0.03 microns is observed.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call