Ketil Pettersen

Microstructure and mechanical properties of high pressure die cast magnesium alloy AE42 with 1% strontium

Abstract The addition of 1 wt-%Sr to AE42 results in an improvement in the tensile strength of the alloy at elevated temperatures of 150 and 175°C and an improvement in the constant load creep properties at 175°C. The improved elevated temperature tensile and creep strength of the alloy can be attributed to the presence of a strontium-containing phase in the microstructure of the alloy along with an increase in the stability of the microstructure of the alloy at high temperatures.

Die Cast Magnesium Alloys for High Temperature Applications

The development of creep resistant alloys for automotive drive train components has proven to be metallurgically challenging. This paper discusses the principles of high temperature alloy development, featuring metallurgical, microstructural and processing aspects of some alloys, relative to their high temperature performance. The creep resistant alloys within the Mg-Al base system obtain their creep resistance by a relatively low content of Al, and addition of elements that form stable intermetallic phases within the grain mantle. Various third elements affect the high temperature performance differently. The results demonstrate that rare earth elements (RE) show a remarkable potential as the third element(s).

CALORIMETRY AND WETTABILITY TESTING TO EVALUATE THE EFFECT OF SURFACE OXIDATION OF SiC PARTICLES IN PRODUCTION OF Al-PMMC.

The relative wettability of various surface modified SiC particles are measured in different aluminium alloys. Both surface treatment and alloying elements gave only small effects on wettability. Interfacial reactions like Al4C3 formation promotes the wettability in the system Al-SiC. Al4C3 is an unwanted interfacial reaction product because of both process technical reasons and influence on the mechanical strength of the final product. DSC (differential scanning calorimetry) showed that the system had not reached equilibrium during the wettability experiment. To avoid Al4C3 formation the DSC experiments showed that a surface treatment of the SiC particles is necessary. Alternatively a certain concentration of the alloying element Si, as determined by DSC is needed.