| Based on the investigation of a large amount of the related academic literatures at home and abroad, a series of new heat-resistant magnesium alloys have been investigated based on AE41 alloy by Ca and Si alloying as well as substituting LPC (La-Pr-Ce) mixed rare-earth metal for Di (Nd-Pr) mixed rare-earth metal in this paper. Their microstructure was analyzed by optical microscope(OM), scanning electron microscope(SEM), X-ray diffraction(XRD) and energy dispersive spectroscopy (EDS). Their tensile properties experiment was carried out on the electro-universal testing machine, and their indentation creep properties were tested on the Brinell Tester at 150℃and 175℃. The main results are presented as follows.1. Ca can refine the microstructure of AE41 alloy and tend to change the microstructure morphorlogy configuration from dentritic to equiaxial grain with the increase of Ca addition. There are two kinds of precipitation phases in the Ca-containing AE41 alloys, one is the skeleton- shaped Al2Ca phase existed in the grain boundary, another is the short rod-like Al2Di phase existed within the grain and in the grain boundary. The tensile properties of the Ca-containing AE41 alloys are the same as that of AE42 alloy, and their creep-resistant properties are better than that of AE42 alloy. The reason that Ca can improve the elevated temperature properties of AE41 alloy, especially the creep-resistant properties, is that the heat-resistant phases Al2Ca and Al2Di distribute homogeneously in grain boundaries and do not change at elevated temperature, while the needle-shaped Al11Di3 strengthening phase of AE42 alloy will decompose into the short rod-like Al2Di phase at above 150℃. |
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