Measurement Of Thermal Physical Properties Of Aluminum-based And Magnesium-based Alloy Melt And Application

Study on thermal physical properties (viscosity, surface tension and wettability etc) of aluminum and magnesium melt is an indispensable component of liquid physical field and it is extensively concerned in recent years. The preparation of melt direct foaming route is intimately related to thermal physical properties of aluminum and magnesium melt, such as effects of viscosity of alloy melt on drainage and stabilization of liquid foams, the relation of surface tension and nucleation and growth of bubbles and effects of wettability on the structure of foam of metal foam etc. In addition, the properties are also closely connected with liquidity, segregation and solidification of alloy melt. Research on thermal physical properties of aluminum, magnesium alloy melt with various constituents as the supervision of preparation of aluminum,magnesium foam is of great importance since the alteration of alloy constituents directly results in that of melt property.In this paper, the elements of Ca, Mg and Si were added into pure aluminum melt, elements of Ca,Al and the particle of SiC were added into pure magnesium melt. The viscosity of binary alloy melt Al-Ca and Al-Si, ternary alloy Mg-12Al-3Ca and composite material of Mg-12Al-3Ca/SiC were measured using the high temperature melt viscosity instrument of the rotary vibrationtype; Surface tension of binary alloy melt Al-Ca, Al-Si and Al-Mg and ternary alloy melt Al-3%Ca-Mg and Al-3%Ca-Si and Mg-12Al-3Ca and composite material of Mg-12Al-3Ca/SiC were determined using maximum bubble method, the device of drop method of determinating contact angle was installed. Meanwhile the aluminum foam was prepared, and the apparent characterization was performed. The results are shown as follows:(1) The viscosity of pure aluminum melt rises with the increase of Ca element while its surface tension adversely reduces. Surface tension decreases with elevated temperature; The viscosity of alloy melt reduces with increasing Si element while its surface tension adversely increases; Surface tension of alloy melt reduces with the increase of Mg element.(2) In contrast to that of the binary alloy melt Al-3%Ca (mass fraction, the same below) the viscosity of the ternary alloy melt Al-3%Ca-Mg all decrease while surface tension adversely with the increase of Mg element. Compared with those of the binary alloy melt Al-3.0%Ca, the viscosity of the ternary alloy melt Al-3.0%Ca-Si all decrease with the increase of Si element while surface tension adversely rise.(3) In contrast to that of the alloy melt Mg-12Al-3Ca, the viscosity of composite material all decrease while surface tension all rise.(4) The apparent density of aluminum foam decreases with the increase of Ca element and accordingly the porosity ascends as melt direct foaming route is applied. Uniform cell structures of aluminum foam can be achieved under the condition. Density of aluminum foam with constant addition of Ca (3%) element goes down firstly and then goes up as the content of Mg element gradually increases. Interior cracks and bubble coalescence of aluminum foam appear as the addition of Mg element more than1%.