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Abstract: The effect of Cr content on the self-propagating high temperature synthesis (SHS) reaction of Cr–Ti–C system has been investigated in this research. The thermodynamics calculation indicates that the TiC possesses higher thermodynamic stability than the Cr23C6, Cr7C3 and Cr3C2 phases, and the formation of TiC is the most exothermic. Additionally, the adiabatic combustion temperature (T ad) decreases with the increase of Cr content except for the phase transition regions. The XRD result shows that the type of products synthesized by SHS changes that a higher Cr content corresponds to higher chromium carbide. When Cr content is 10wt.%, only solid solution (Ti,Cr)Css is formed in the products. When Cr content increases to 20wt.%, besides (Ti,Cr)Css, the Cr7C3 phase is also detected. With the Cr content further increasing to 30 and 40wt.%, the products consist of (Ti,Cr)Css, Cr23C6, Cr7C3 and Cr, and therefore, much higher chromium carbide is synthesized. When Cr content reaches 50wt.%, however, the Cr7C3 disappears and the final products become (Ti,Cr)Css, Cr23C6 and Cr. Moreover, when Cr content increases from 10 to 20wt.%, the lattice parameter of (Ti,Cr)Css decreases, while it increases when the Cr content ranges from 20 to 50wt.%. Furthermore, the microstructure shows that the TiC particulate size decreases from ∼8 to ∼2μm with the increase of Cr content from 10 to 50wt.%, and the morphology shape of TiC particulate becomes more and more spherical. [Copyright &y& Elsevier]

Abstract: The evolution process of TiC formation in the 20wt.% Cu–Ti–C powder mixtures was studied by using differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The Ti x Cu y compounds (Ti2Cu, TiCu, Ti3Cu4 and TiCu4) formed initially via solid-state diffusion reactions between Cu and Ti particles; and then Ti2Cu and TiCu can form a Cu–Ti eutectic liquids at about 1233K. The unreacted Ti and C particles dissolved into the Cu–Ti liquids and led to the formation of Cu–Ti–C ternary liquids; subsequently, TiC particulates precipitated out of the saturated liquids. At the same time, also the formation of Ti2Cu occurred at the interface between the Cu–Ti liquids and the unreacted Ti particles. As the temperature increased further, the Ti2Cu melted and more Cu–Ti liquids formed; and then C particles continuously dissolved into the Cu–Ti–C liquids and TiC particulates gradually precipitated out of the saturated liquids. [Copyright &y& Elsevier]

Abstract: In the Co39Ni33Al28 alloy, the ferromagnetic shape memory effect was investigated. A martensitic transformation (MT) occurred in the Co39Ni33Al28 alloy when the temperature was lower than the martensitic start transformation temperature, M S =233K. The morphologies and microstructures of the martensitic phase characterized by transmission electron microscope (TEM) showed a new 28-layered (28M) modulated martensite consisting of pinstripes and co-existing with the non-modulated martensite. Anomalies in magnetic properties and strain emerging around the MT have been briefly discussed. [Copyright &y& Elsevier]

Abstract: The Mg–30B2O3 modifier with the composition of Mg and B2O3, sintered in the temperature range between 250 and 450°C, has been developed as a low-cost and effective modifier for hypereutectic Mg–Si alloys. With 0.2–1.0wt.% B (introduced in the form of Mg–30B2O3), the morphology of the primary Mg2Si transforms from coarse dendrite shape into fine polyhedral shape with the size about 10μm. The modification mechanism of B2O3 is attributed to the adsorption and poisoning manners due to the presence of B in the melts by the decomposition of B2O3. [Copyright &y& Elsevier]