Abstract
The effect of the coating materials of the tools on the dynamic friction characteristics and microstructural evolution with straining was investigated by the ring-typed compressive test at a temperature of 473 K and at a strain rate of 10−2 s−1 in the extruded AZ31 magnesium alloy with an average grain size of 15 μm. The values of the dynamically recrystallized grain size in the samples compressed up to about 45% by using the WC-Co tools with and without the DLC coating were 3.8 μm and 4.8 μm, respectively. The dominant deformation mechanism under all the testing condition for the present alloy was the climb-controlled dislocation creep. The dynamic friction coefficient, m value, for the sample compressed by the WC-Co tool was higher than that done by the DLC tool, even if though there was identical tendency in stress level. The integration degree of the grains within 10 degree from ⟨0001⟩ direction to compressive axis in the sample compressed by the WC-Co tool was larger than that done by the DLC tool. It was concluded that the higher m value could enhance an alignment of the planes perpendicular to the compressive direction to the basal plane even if under same testing condition.
