Dynamic Friction Properties and Microstructural Evolution in AZ31 Magnesium Alloy at Elevated Temperature during Ring Compression Test

The dynamic friction properties of the extruded AZ31 magnesium alloy with the initial average grain size of 15 μm were investigated by the ring compression test at 473 and 523 K and in a strain rate range from 1.0×10−2 to 3.0 s−1. Two types of the tool, WC-Co tool (WC) and WC-Co coated with diamond like carbon tool (DLC) were used. At 523 K, few differences in terms of the friction coefficient were observed due to the difference with or without DLC. At 473 K, the friction coefficient for the sample deformed by DLC tool was smaller than that done by WC tool. The investigation of the texture near the surface of the tested work pieces with different tools reveals that the integration degree of the grains within 10 degree from 〈0001〉 direction to compressive axis in the sample deformed by the DLC tool was smaller than that done by WC tool. It was concluded that the larger friction could enhance alignment of the planes perpendicular to the compressive direction to the basal plane even if under same testing condition.