Comparison of Age-Hardening Characteristic in Thixo-Cast and Rheo-Cast T5-A356 Alloys by Nanoindenter and AFM
The nano/microstructure and mechanical/tribological properties of the eutectic regions in thixo/rheo-cast A356 alloy parts were investigated using nano/micro-indentation and mechanical scratching, combined with optical microscopy and atomic force microscopy (AFM). Most eutectic silicon crystals in the A356 alloy showed a modified morphology as fine-fibers. The aging responses of the eutectic regions in both the thixo/rheo cast A356 alloys aged at 150 0C for different times (0, 2, 4, 8, 10, 16, 24, 36, and 72h) were investigated. Both Vickers hardness (HV) and indentation hardness (HIT) test results showed almost the same trend of aging curves, the peak was obtained at the same aging time of 10 h, and in tribological properties of thixo/rheo-cast, the friction coefficient of thixo-cast was investigated lower than that of rheo-cast.
N. Ohno and T. Uehara
S.H. Cho et al., "Comparison of Age-Hardening Characteristic in Thixo-Cast and Rheo-Cast T5-A356 Alloys by Nanoindenter and AFM", Key Engineering Materials, Vols. 340-341, pp. 919-924, 2007