Hardness and Electrical Resistivity Changes during Ageing of Rapidly Solidified Al-12.5Si-1Mg Alloy
Ribbons with the composition Al–12.5Si–1Mg were prepared by melt spinning. X-ray diffraction of as melt spun ribbons showed complete solubility of Si in aluminum. The as melt spun resistivity was 36 μΩ cm for ribbons of 24 μm thickness. This value relaxes to 9.0 μΩ cm on prolonged annealing. The hardness of the as melt spun ribbons was 1500 MN/m<SUP>2</SUP>, and relaxes to reach a value of 800 MN/m<SUP>2</SUP> after prolonged annealing. The activation energy estimated from isothermal ageing ranged from 1.05 to 1.26 eV. An equation is given to fit the kinetics of relaxation. Discussion of resistivity and hardness relaxation is given and is related to ordering and silicon precipitation.
- Materials transactions, JIM
Materials transactions, JIM 38(5), 401-405, 1997-05