The thermal conductivity, electrical resistivity, and mechanical properties of a sintered iron-copper alloy. Part 2

Abstract

1. It was established in this investigation that, when 15% nickel is added to an iron-copper-graphite alloy containing after sintering 1.1% C and 10% Cu, the hardness of the alloy increases by 20–25%, but, at the same time, its mechanical strength, ductility, and impact strength decrease compared with the same properties of a similar nickel-free alloy. 2. Other conditions being equal, sintering in a dissociated ammonia atmosphere reduces the mechanical and impact strengths by approximately 10–15% and slightly decreases the ductility compared with the properties of the same alloy sintered in a hydrogen atmosphere. 3. The tensile and impact strength tests of specimens at 400°C revealed a slight decrease in the mechanical and impact strengths at that temperature. 4. The thermal conductivity increases linearly with increasing temperature. The Lorenz function is greater than its theoretical value, and decreases with increasing temperature. This indicates that heat conduction in this alloy is due to conduction electrons and crystal-lattice conduction. 5. The coefficient of linear thermal expansion at first shows an insignificant increase, but at 400°C attains values characteristic of cast austenite.