Hiroyuki Kawabata

Influence of Alloy Composition on Cast Cracking and Heat Resistance of Mg‐Al‐Ca Cast Alloy

Magnesium alloys are important materials since they can be used to significantly reduce the weight of automobiles, but their application has been limited thus far. One possible way to extend the usage of magnesium alloys is applying them to peripheral parts of the engine that are large, have complicated shapes, and are exposed to high temperatures under the loaded condition. However, heat-resistant magnesium alloys always have poor castability, since such alloys have a lot of intermetallic compounds with poor ductility.

Microstructures and Mechanical Properties of Mg-1at%X Alloys Processed with High-Pressure Torsion

A number of researchers have reported the mechanical properties of Mg alloys processed with high-pressure torsion (HPT), which is a typical method of severe plastic deformation. However, the effect of alloying elements on the mechanical properties of HPT-processed Mg alloys was unclear.

Influence of Aluminum Content on Corrosion Resistance of Mg‐Al Alloys Containing Copper and Zinc

The corrosion resistance of Mg-Al alloys deteriorates significantly with increasing copper content. Consequently, the tolerance limit of copper is commonly fixed at less than 300 ppm in Mg-Al alloys to ensure they have sufficient corrosion resistance. However, it is desirable to use higher copper tolerance limit in actual operations. To realize this, it is very important to prevent the deterioration in the corrosion resistance with increasing copper content. In this study, Mg-Al alloys with different aluminum, zinc, and copper contents were casted by high-pressure die casting and the corrosion resistances of the castings were investigated. The corrosion resistance of Mg-9% Al alloys decreased significantly with increasing copper content. However, adding zinc to copper-rich alloys prevented the reduction in the corrosion resistance due to copper. The corrosion rate of Mg-Al alloys containing 0.5% copper and 3% zinc was minimized at an aluminum content of 9%. The corrosion resistance of Mg-Al alloys containing copper and zinc was highest at a zinc content of over 3% and an aluminum content of about 9%.

An Automatic Offsetting Method of Composite Surfaces

In the process of modelling the inner surface of resin parts for an automobile, we have usually offset competent surfaces of the outer model and relied on tedious joining operations to guarantee the integrity of the result. Consequently, considerable amount of manpower has been required for this process.