M. Nakanishi

Tensile properties at elevated temperature of W-1%La2O3

The tensile properties were investigated from 1273 to 1973 K for recrystallized pure W and W-1%La2O3. The WLa2O3 showed much higher strength than the pure W, but slightly lower elongation, except at 1273 K where the pure W suffered from intergranular fracture. The excellent mechanical properties of the WLa2O3 are probably the result of the structure, consisting of elongated grains, which resists grain boundary sliding.

The aging behavior and the mechanical properties of the Mg-Li-Al-Cu alloy

The purpose of the present work is to improve the elongation of the b.c.c. single phase Mg-Li-Al alloys by the addition of the fourth alloying element. As the fourth alloying element, the authors have chosen copper because it is slightly soluble in magnesium and is expected to act as the nucleation sites for precipitates in this alloy; many nucleation sites for the precipitates are introduced into the Mg-Li-Al alloy so that the precipitates particles are finely and uniformly dispersed. Hence, it is expected that a good combination between high tensile strength and high elongation is obtained. The authors have investigated the relationship between aging behavior and the mechanical properties of the Mg-37.5 at%Li-0.7 at%Al-0.4 at5 Cu alloy.

Effect of thermal cycling on the properties of SiC whisker-reinforced aluminium alloys

This study was carried out to examine whether the same degradation occurred in the case of SiC whisker-reinforced aluminium alloy fabricated by squeeze casting, when it was subjected to thermal cycling

Application of equal channel angular extrusion on strengthening of ferritic stainless steel

SUS430 ferritic stainless steel was subjected to equal channel angular extrusion (ECAE) at room temperature to a total strain of 2.3. It was shown that the sample processed by ECAE showed higher room temperature strength than the as-quenched sample. This is probably due to the heavily worked structure. On the other hand, annealing at 673 K and 773 K increased both strength and elongation of the ECAE processed sample. It is likely that higher strength is attributed to both the worked structure and fine substructures. It is also likely that higher elongation is attributed to the fine substractures. It is concluded that a combination of ECAE with annealing is available for improving the room temperature tensile properties of SUS430.

Fatigue of Alumina Short Fiber / Aluminium Alloy Composites

Cyclic bending fatigue tests were performed on alumina short fiber reinforced JIS AC8A alloys, to examine the effects of volume fraction of fibers and nonfibrous inclusions (shots) on the S-N curve. Fatigue limit stress rose with increasing volume fraction of fibers and the effect of shots was very small when shots content was less than 0.1%. Cyclic fatigue crack propagation was also measured on the composites. The sensitivity of the composites to pre-crack increased greatly with increasing volume fraction of fibers.