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Casting Temperature (casting + temperature)
Selected AbstractsThe Effects of Casting Temperature on the Glass Formation of Zr-Based Metallic Glasses,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Jie Mao Abstract The glass1-forming ability of two alloys, Zr64.9Al7.9Ni10.7Cu16.5 and Zr47Cu37.5Ag7.5Al8, prepared by arc-melting a mixture of Zr, Cu, Al, Ni and Ag elements is studied as a function of casting temperature. Other processing parameters such as the alloy melt mass, and the vacuum and injection pressures during the copper-mold-casting process are kept constant so just the influence of the casting temperature is considered. The casting temperature determines the characteristics of the liquid melt and the cooling rate. The glass-forming ability is discussed in terms of dissipation of pre-exiting, metastable local-ordering clusters that act as nucleation sites promoting crystallization, the cooling rate at high casting temperatures, and the presence of oxygen in the alloys, which is increased at high casting temperatures. It is found that the glass-forming ranges of alloys shrink as the glass-forming size approaches a critical value. The optimum temperatures are around 1450,K and 1550,K for Zr64.9Al7.9Ni10.7Cu16.5 and Zr47Cu37.5Ag7.5Al8 alloys respectively. The alloys were studied by XRD, TEM, oxygen-level determination, and DSC. [source] Stretching induced phase transformations in melt extruded poly(vinylidene fluoride) cast films: Effect of cast roll temperature and speedPOLYMER ENGINEERING & SCIENCE, Issue 12 2007Milind V. Mhalgi Melt extruded poly(vinylidene fluoride) cast films were prepared at different cast roll temperatures and speeds to study the effect of casting temperature and preorientation of the melt on the ,- to ,-phase transformation in these films after uniaxial stretching. X-ray and fourier transform infrared spectroscopy were used to identify the crystalline phases. The unstretched films were characterized using small angle light scattering (SALS). The films were stretched to a stretch ratio of 4.2 and at 80°C. Birefringence of the films and the fraction of ,-phase [F(,)] formed after uniaxial stretching increased with stretch ratio. The films showed increased crystallinity after stretching. For the films prepared at different cast roll temperatures, there was little change in F(,) in the films having a cast roll temperature between 75 and 120°C, but for the film with a cast roll temperature of 130°C F(,) decreased considerably. For the films prepared at different cast roll speeds, the F(,) increased with stretch ratio as well as with cast roll speed for a fixed stretch ratio. The primary effect of changing both the parameters is a change in the average spherulitic radius (R), in the unstretched films measured using SALS. The F(,) obtained correlated well with R and lower spherulitic radii resulted in the higher conversion to the ,-phase. POLYM. ENG. SCI., 47:1992,2004, 2007. © 2007 Society of Plastics Engineers [source] The Effects of Casting Temperature on the Glass Formation of Zr-Based Metallic Glasses,ADVANCED ENGINEERING MATERIALS, Issue 12 2009Jie Mao Abstract The glass1-forming ability of two alloys, Zr64.9Al7.9Ni10.7Cu16.5 and Zr47Cu37.5Ag7.5Al8, prepared by arc-melting a mixture of Zr, Cu, Al, Ni and Ag elements is studied as a function of casting temperature. Other processing parameters such as the alloy melt mass, and the vacuum and injection pressures during the copper-mold-casting process are kept constant so just the influence of the casting temperature is considered. The casting temperature determines the characteristics of the liquid melt and the cooling rate. The glass-forming ability is discussed in terms of dissipation of pre-exiting, metastable local-ordering clusters that act as nucleation sites promoting crystallization, the cooling rate at high casting temperatures, and the presence of oxygen in the alloys, which is increased at high casting temperatures. It is found that the glass-forming ranges of alloys shrink as the glass-forming size approaches a critical value. The optimum temperatures are around 1450,K and 1550,K for Zr64.9Al7.9Ni10.7Cu16.5 and Zr47Cu37.5Ag7.5Al8 alloys respectively. The alloys were studied by XRD, TEM, oxygen-level determination, and DSC. [source] | ||||||||||