Investigation Of Effect Of Geometry Design On The Corrosion Performance Of Mg Component Using Experiments And Numerical Model

The effect of geometry design on the galvanic corrosion of magnesium component was investigated by experimental measurements and boundary element method(BEM) simulation. A magnesium corrosion test platform was designed based on the joining area of a magnesium engine mount bracket. It contains various geometric design and galvanic corrosion insulation.In this paper, the magnesium engine mount in the Cadillac ATS is the research prototype, a magnesium corrosion test platform was design by Unigraphics NX based on the joining area of it. The AXJ530 magnesium alloy was used to manufacture the galvanic corrosion test platform by CNC. A piece of aluminium alloy A380 was joint with a hole of corrosion test platform by an alloy steel bolt and AISI 1045 nut, isolated by an Al 6061 washer, to form the galvanic couples. 22 kinds of geometry design and some insulation strategies were put on this galvanic corrosion test platform.Both vertical hole and horizontal hole are effective to improve the corrosion performance of magnesium component at the joining region and horizontal hole has a better improvement compared with vertical drain hole. When the attitude of drain hole is lower in vertical direction, the corrosion performance becomes worse insteadly. Larger vertical hole is preferred in the geometry design of magnesium component and the minimal acceptable size of vertical hole is 3.6 mm. Both cone slope and bevel slope are beneficial to the corrosion performance of magnesium component at the joining region. Larger angle of slope is preferred both for cone slope and bevel slope. However, 15° angle is the most effective angle for bevel slope. Moreover, only combined drain hole and slope can the geometry design achieve the optimum corrosion performance under corrosive environments. Simulation based on numerical model shows good agreement with experimental results. It is also indicated that BEM models has the potential in predicting the galvanic corrosion in salt spray conditions.