Plasma Arc Welding Process and Dry Sliding Wear Properties of AlN/AZ91D Magnesium Matrix Composites

摘要

The AZ91D composites reinforced by 10 wt.% AlN particles were welded via plasma welding and the dry sliding wear properties of the composites were investigated. The influence of welding current, welding speed and plasma flow rate were studied in detail. By using of OM, XRD, EDS and SEM, the crystalline phase, the microstructure and the wear properties were investigated. The experiment result shows that the AlN reinforcing particles is in the shape of strip and have a fine size under the condition of the welding speed 400 mm/min, the welding current 180 A and the plasma flow 2.0 L/min, which reaches 20-30 mu m. The matrix grain in the composite were obviously refined, which reaches 60-70 mu m. Wear test results showed that the wear rate of welding seam compared base metal decreased by 25%.