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The crystallisation behaviour of Fe 2 O 3 during preheating and roasting of pellets made from mixed magnetite-haematite (M-H) concentrates has been studied. The results indicate that the strength of pellets is mainly provided by the crystalline connections between Fe 2 O 3 particles during preheating. This occurs because the activity of Fe 2 O 3 from secondary haematite (SH) (oxidised from magnetite concentrate, SH) is higher than from original haematite (OH). In the roasting process, when temperature is lower than 1250uC, the strength is mainly provided by the development, connection and growth of Fe 2 O 3 crystalline grains from SH. Only if the temperature exceeds 1280uC does Fe 2 O 3 recrystallisation in OH grains develop well with the iron ore particles in the pellets fully connected, so increasing pellet strength.

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This paper describes a microstructure-based uniaxial strain-controlled fatigue life prediction model applied to A319 aluminum alloy which is widely used in automobile industry. The materials made with different casting conditions are characterized and quantified in terms of secondary dendrite arm spacing (SDAS), size, and aspect ratio of eutectic Si particles. Uniaxial low cycle fatigue tests have been performed on four groups of A319 alloy under different casting conditions in which cooling rate and Sr addition are variables. It is shown that the effect of various degrees of microstructure on the fatigue life and fatigue behavior is obvious. The first part of the paper is quantitatively characterizing the microstructure of samples to identify the influence of different casting conditions. With regard to mechanic properties, the tensile properties and fatigue behavior of samples are analyzed combining with microstructure. Finally, a microstructure-based Manson-Coffin-Basquin model is proposed to predict fatigue life of Al-Si alloy.

Several poly(vinylidene fluoride-ter-chlorotrifluoroethylene-ter-trifluoroethylene) terpolymers, including 68 mol % vinylidene fluoride, were prepared by the partial reduction of chlorine in poly(vinylidene fluorideco-chlorotrifluoroethylene) copolymers. The terpolymers were then allowed to crystallize under two sets of conditions: (1) crystallized from solution (in N,N-dimethylformamide) at 35 C for 108 h and (2) annealed at temperatures 5 C below their respective melting points for 11 h. The effect of the chlorotrifluoroethylene (CTFE) content and crystallization conditions on the crystallization behavior of the terpolymers was investigated by Xray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry. The results show that with increasing CTFE content, the terpolymers contained less of the b phase (it even disappeared), which had an all-trans chain conformation, and more of the c phase was found, which became prominent with the trans-trans-trans-gauche conformation. The crystallinity, crystal size, fusion enthalpy, and melting temperatures of the terpolymers decreased with increasing CTFE content. Compared with annealed terpolymers, the terpolymers crystallized from the solution at 35 C included more polar components that contained more trans conformations but had lower crystallinities, melting temperatures, and fusion enthalpies and smaller crystal sizes. These results suggest that crystallization from the solution may be helpful in forming polar crystals, whereas an annealing process at a high temperature is beneficial in perfecting the crystal structure.