Derek Raybould

Rapidly solidified Mg-Al-Zn-Rare earth alloys

Among the light metal alloys, magnesium is the lightest structural material except for beryllium, and yet magnesium alloys have not seen extensive use because of their poor strength and corrosion resistance. Rapid solidification technology offers a possible solution to these problems. A number of Mg-Al-Zn alloys containing rare earth (RE) elements (e.g. Ce, Pr, Y, and Nd) have been investigated using rapid solidification processing for possible structural applications. The processing consists of planar flow or jet casting into ribbons, pulverization of ribbon to powder, and consolidation of powder into bulk shapes. The mechanical properties of some of these alloys show attractive combinations of strength (UTS-513 MPa), ductility (tensile elongation-5%) and corrosion resistance [corrosion rate of 11 milligrams per square decimeter per day (mdd) in 3% NaCl solution]. The microstructures of these alloys are correlated with their mechanical properties. The rapidly solidified Mg-Al-Zn-RE alloys show great potential for applications in automotive and aerospace industries.

Rapidly solidified tungsten-based alloys☆

Abstract Rapid solidification of novel variations of WNiFeB alloys has been explored for possible improvement over conventional liquid-phase sintered WNiFe alloys. Ribbons containing between 40 and 75 wt.% tungsten were produced by melt spinning and subsequently pulverized and consolidated using hot extrusion to produce a bulk material. It was found that the as-cast ribbon was either amorphous or microcrystalline and showed increasing crystallization temperature with increasing tungsten content. Upon extrusion, the amorphous structure transformed to a fine multiphase structure of tungsten and Wx(Ni, Fe)By particles in a continuous nickel-based solid solution matrix. An overview of the microstructure and properties is discussed.