ショットライニング処理したマグネシウム合金の表面特性

抄録

In recent years, against the background of reducing environmental pollution, in the field of transportation equipment such as automobiles and aircraft, there has been an active movement to use light metals as a substitute for steel materials. Magnesium alloys and aluminum alloys are characterized by high specific strength due to their lightness. However, these light alloys have the problem of lower corrosion resistance and wear resistance than steel materials. Therefore, when used as the actual materials, it is necessary to apply surface treatment. In the present study, to improve the corrosion resistance of magnesium alloys, we performed jointing of dissimilar metal foils using shot peening. In the joining of metal foils, bondability and corrosion resistance were investigated. The experimental materials were extruded round bars of commercially available Mg alloys AZ31, AZ61, AZ80 and AZX611. The different metal foils were pure titanium foil, pure copper foil, pure nickel foil, and stainless steel foil with a thickness of 0.02 to 0.04 mm. Joining was performed using a centrifugal shot peening device with a prototype heating device built into it. The workpieces were heated to 300 to 350°C to improve the bondability between the metal foil and the base material. Using a digital optical microscope, the surface and cross-section observations of the joined workpieces were performed. In addition, a three-point bending test was performed to examine bondability. To examine corrosion resistance, immersion in a supersaturated sodium chloride aqueous solution was performed. Joining of dissimilar metal foils such as titanium foil and nickel foil to magnesium alloys showed good bondability at a working temperature of 300°C. In corrosion test, the corrosion resistance of magnesium alloy was improved by joining the corrosion-resistant metal foil. The joining of corrosion-resistant metal foils by this technique was effective in improving the corrosion resistance of magnesium alloys.