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In this paper, a study on the innovative hot stamping process and the typical microstructures is presented, aiming to clarify insights into the influence of processing variables (asymmetric rolling temperature, rolling reduction, pre-heating method, and so on) on the evolution of microstructure, in order to evaluate the feasibility of the new process to improve properties of 22MnB5 steels. TEM investigations of asymmetrically rolled samples indicate different morphologies of dislocation density and pearlite with altering the rolling reduction, velocity ratio (VR) and rolling temperature. And the study demonstrates that asymmetric rolling before hot stamping process greatly promotes the austenite transformation during the pre-heating stage, especially when the rolling temperature is lowered to liquid nitrogen temperature (LNT) and the velocity ratio is higher than 1.5. And two-step pre-heating with induction heater and roller hearth furnace contributes positively to the austenite grain refinement in pre-deformed 22MnB5 steel. Another relevant conclusion is that the cooling microstructures can also be adjusted by changing the pre-deformed temperature of the samples.

This paper investigated the solid-state graphitization of spherical graphite iron by electropulsing annealing. The results indicated that the electropulsing annealing can accelerate the decomposition of cementite, improve the diffusion ability of carbon in the matrix and make more neonatal graphites in small size be formed. With the increase of electropulsing annealing temperature, the graphitization rate is accelerated. At the high temperature and the quick heating rate, the solid-state graphitization can be finished in a short time. Analysis shows that electropulsing annealing promotes the nucleation of graphite and the decomposition of cementite, consequently, the solid-state graphitization of spherical graphite iron is accelerated.

Al–5.5Cu/TiB 2 and Al–5.5Cu/TiAl 3 in situ composites were made by spray deposition. The microstructures, interface structures of the composites were analyzed by X-ray diffraction, SEM and TEM. The results show that the grain size is 15–20 μm, and that the size of TiB 2 is 1–2 μm. There are certain orientation relationships between TiB 2 and α-Al, and TiAl 3 and α-Al. It is shown that the tensile strength of spray-deposited Al–5.5Cu/TiB 2 is 452 MPa, and the ductility is 14%. The properties of the composites are improved obviously beyond those of conventionally cast composites.

The gas pressures at the tip of the melt delivery tube in two typical atomizers are measured in this work. Gas dynamics is used to study the gas flow and pressure zone at the tip of the delivery tube, and a mechanism for the formation of pressurization and aspiration is proposed. The results show that the atomization efficiency of an atomizer with a Laval nozzle is superior to that of an atomizer with a converging nozzle. The gas jet expands strongly at the nozzle exit of a converging atomizer, while the Prandtl–Meyer angle of the jet is very small for a Laval nozzle. When the jet expands strongly, pressurization is likely to form at the tip of delivery tube. Aspiration is formed when the jet pressure at the exit of nozzle is equal to or smaller than the back pressure.

This paper reports an experimental investigation into the use of the spray forming process to a high strength, high conductivity, copper alloy of composition Cu–1.33 wt.% Cr–0.78 wt.% Zr–0.09 wt.% Mg, with a refined microstructure increased solid solution of alloy elements, reduced oxidation and a high proportion of small precipitates.