Titanium boride (TiB₂) particles were synthesized in aluminum matrix by a combustion reaction of Ti–B–Al preform, aiming at synthesizing nano-scale fine particles. The formation behavior of TiB₂ particle was observed by Combustion Front Quenching Method (CFQM) , in which self-propagating combustion wave was terminated by heat absorption of metallic mold. At the earliest stage of the reaction, the reaction between aluminum and titanium took place, and boron was not involved in the reaction. The nucleation site of TiB₂ was a peripheral area of boron particles. TiB₂ particles synthesized at the early stage of the reaction was very fine (~200 nm) , and the growth of particles occurred during a high-temperature stage of the combustion reaction. The effect of powder blending ratio on the size of TiB₂ particle was examined. The combustion temperature was reduced by increasing aluminum fraction in the preform. The synthesized TiB₂ particle was effectively refined by increasing the blending ratio of aluminum. By using finer boron particles or by increasing boron fraction in the preform, TiB₂ particle was also refined effectively.

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Effect of the heat treatment at 443 K has been investigated on plastic properties and drawability in a cold rolled 3004 aluminum alloy sheet for D&I cans. After the heat treatment, r value decreases in 60–90 degree to the rolling direction. Therefore, the anisotropy of r value is slightly improved and the average of r value decreases a little. However, the earing does not change. The anisotropies of work hardening exponent n value and F value are also reduced by the heat treatment. The tensile strength and the yield strength slightly goes down and total elongation increases. According to these changes, the drawability of the sheet goes up and the uniformity of thickness and hardness distribution in the drawn cup's wall are improved. The anisotropy change of plastic properties is considered to depend not only on the precipitation but also the partial recovery of anisotropic deformation bands and dislocation structures strongly developed in the cold rolled sheet.

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For CO₂ emission reduction, an incremental flattening process in which sheet metal waste is recycled with non-heating has been proposed. In this process, a bent sheet is unbent into a sheet metal with a triangular residual corner, and this residual corner is flattened incrementally. During the incremental flattening, the thinned bent corner can be thickened. However, this incremental flattening process has a problem in which the thickness of the bent corner after flattening is thinner than the thickness of the surroundings. To overcome this problem, we investigated the thickening behavior of the bent corner during the incremental flattening and experimentally clarified the possibility of the increase in the thickening of the bent corner from considering of this thickening behavior. It was found that the bent corner buckled during incremental flattening. Experimental results showed that this buckling of the bent corner was controlled by shortening the length of the triangular side of the residual corner, and the thickening of the bent corner increased. Furthermore, work-hardening exponent of sheet metal influenced on the thickening of the bent corner.

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For CO₂ emission reduction, a cold recycling process of sheet metal wastes has been proposed. In this process, a bent sheet of sheet metal waste is unbent into a sheet metal with a triangular residual corner, and this residual corner is incrementally flattened. The thinned bent corner can be thickened during the incremental flattening. However, this flattened sheet has a groove on the center of the thickened region, i.e., the thickness of the bent corner after flattening is thinner than the thickness of the surroundings. In the cold recycling, this groove should influence on the forming limit of the flattened sheet metal. Here, we focused on this groove and experimentally investigated the possibility of cold recycling of 5052 aluminum alloy sheets. Although the forming limit of the flattened 5052 aluminum alloy sheet was decreased in that of uniform 5052 alloy sheet, this flattened sheet can be formed into conical shells by incremental forming. Furthermore, it was found that the groove on the thickened region was shallow because of shortening the length of the triangular side of the residual corner, and then the forming limit of this flattened sheet was increased. These experimental results suggest that the forming limit of the flattened 5052 aluminum alloy sheet should be close to that of a uniform 5052 alloy sheet as the groove is shallower.

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It is well known that adhesion of electroless Ni–P coating onto aluminum alloy substrate can be remarkably improved by introducing the double zincate treatment as a pretreatment process. This study investigated the effects of alloying elements and zincate treatment on adhesion of electroless Ni–P coating onto various aluminum alloy substrates by using peeling test, FE-SEM and XPS. Surface morphology of zinc deposit from the 1st zincate treatment and its adhesive strength were changed, depending on the alloying element. The zinc deposit from the 2nd zincate treatment became thinly uniform, and the adhesive strength was improved irrespective of the alloying element. By dipping the zinc deposit obtained at the 1st zincate in 5% HNO₃ solution, most of the zinc deposit on aluminum substrate was dissolved, but XPS analysis revealed that the existence of zinc, whose condition was metal, at the surface of aluminum alloy substrate after this dipping. This zinc at the surface should be an important factor influencing morphology of zinc deposit at the 2nd zincate treatment, so that zinc deposit became highly uniform and thin. This zinc at the surface can be attributed to the diffusion of zinc and aluminum between the zinc deposit from the 1st zincate and the aluminum alloy substrate.

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