Abstract
Two alloys (Mg-2Y-2Gd-1Ca and Mg-2Y-2Nd-1Ca) specially designed for use in aerospace industry, were processed by eight passes of Equal Channel Angular Pressing (ECAP) method. Processing led to a uniform ultrafine-grained microstructure with a grain size ~1 µm and a dense distribution of submicrometer precipitates. Microstructure, mechanical properties and ignition temperature were investigated. Obtained results were compared with commercially available alloys AZ31, AE42, AX41 and WE43, also processed by eight passes of ECAP.
The newly designed alloys are characterized by higher values of yield tensile/compressive strength (over 250 MPa) and higher Vickers microhardness values in comparison with commercial alloys, except WE43. Nevertheless, the segregation of calcium at the grain boundaries led to a significant reduction in ductility.
Chemical composition of novel alloys led to the formation of stable oxide layer when exposed to the elevated temperatures resulting in exceptional high ignition temperatures >900 °C. This is higher compared to commercial alloys with the exception of WE43, which however contains a larger concentration of rare earth metals, which makes it more expensive and less promising for the utilization in the aerospace industry.