Magnesium (Mg) alloys have received extensive attention in industrial applications due to their low density, low modulus of elasticity, high-specific strength, and high-specific stiffness. [1-4] However, the low-temperature formability [5] and low corrosion resistance [6-8] of Mg alloys limit their large-scale applications. Many researches have indicated that the impurity elements, Fe, Ni, Cu, Co, in Mg alloys can strongly increase their corrosion rate, [9-11] and also severely deteriorate the mechanical [12-14] and damping properties. [15] When the impurities content in alloys exceeds the "tolerance limit" (10 ppm magnitude), the corrosion rate of Mg alloys will be exponentially accelerated. [16] Therefore, it is of great significance to strictly control the purity of the Mg alloys, especially the purity of the molten alloys before casting. Unfortunately, it is almost impossible to completely avoid these impurities during the production of Mg alloys. First, during Mg-metal smelting, no matter whether the Pidgeon method or the electrolytic magnesium method is used, there are always some impurities picked up from the raw materials. Second, these elements existing in the steel tools and steel crucibles can be dissolved in the molten Mg alloys during the melting process. [17-20] The purification of the molten Mg and Mg alloys has been studied extensively. [21-24] However, the effect resulting from defined tools on the Mg alloys production is rarely studied. [19,25] Scharf and Ditze [19] studied the interaction layers between AZ91 and AS31 with steel crucibles. The dissolution of iron, lowcarbon steel, and SUS316 (11wt% Ni, 17wt% Cr, remainder Fe) crucibles in commercial pure molten Mg was investigated by Taninouchi et al. [25] However, the influence of the types of used steels on the purity of molten Mg alloys has not been studied. Only by understanding the specific impact of elements coming from the tooling materials on the purity of molten Mg alloys can assure the purity of Mg alloys. This work aims to quantitatively determine the effect of tooling materials on the purity of Mg alloys melt. The most commonly cast Mg alloys, AZ91D, and AM50A, were studied. Three types of common tooling materials used in the production of Mg alloys: 20# steel, H13 steel, High-CrNi (022Cr25Ni7Mo4N) steel, were studied. Low carbon steel (here 20#) is the most common material used as the crucible materials for the Mg alloys synthesis. H13 steel is commonly used for Mg alloys casting molds. High-CrNi heat-resistant steel is commonly seen for the reduction tank in the Pidgeon process. The interactions between these tooling materials and Mg alloys were pre-evaluated using the Thermo-Calc 2019 software [26] based on the TCMG5 thermodynamic database. The influence of tooling materials on the purity of molten Mg alloys was experimentally studied using the liquid-solid diffusion method. What is more, the thermodynamic information is very important for the effective alloy design as well as the prediction of the distribution of impurities in al...

The effect of the Al content on the microstructure and mechanical behaviour of Mg–8Li– xAl–0.5Ca alloys is investigated. The experimental results show that an as-cast Mg–8Li–0.5Ca alloy is mainly composed of α-Mg, β-Li and granular Mg2Ca phases. With the addition of Al, the amount of α-Mg phase first increases and then decreases. In addition, the intermetallic compounds also obviously change. The microstructure of the test alloys is refined due to dynamic recrystallisation that occurs during extrusion. The mechanical properties of extruded alloys are much more desirable than the properties of as-cast alloys. The as-extruded Mg–8Li–6Al–0.5Ca alloy exhibits good comprehensive mechanical properties with an ultimate tensile strength of 251.2 MPa, a yield strength of 220.6 MPa and an elongation of 23.5%.

The magnetic shape-memory alloy NiCoMnIn shows, in monocrystalline form, a large reversible magnetic-field-induced strain (MFIS). But it is difficult to achieve the properties in polycrystalline NiCoMnIn alloys. The technique of powder metallurgical preparation of NiCoMnIn foam was studied to improve the properties of polycrystalline NiCoMnIn alloys in the present paper. We introduced a processing route including choosing appropriate space-holding fillers, sintering NiCoMnIn alloy and the filling agent with appropriate grain size. The sintering temperature and time and the optimum volume fraction of the filling agent were determined by analysis of the structure of sintered bulk foams.