摘要:
A metal sintered body composite material which can exhibit superior seizure resistance even when light metal is softened, and a method for producing the same. The production method uses iron base raw material powder including C and one of Cr, Mo, V, W, Mn, and Si, and comprises the steps of forming and sintering a powder compressed article so as to obtain a porous metal sintered body having a space lattice structure having pores, impregnating the pores of the porous metal sintered body with an aluminum alloy and solidifying the aluminum alloy, applying aging treatment by heating and holding the composite material at an aging treatment temperature range, whereby a metal constituting the porous metal sintered body has a micro-Vickers hardness of 200 to 800.
摘要:
A light metal alloy cast piston including a thermal strut (32, 48, 52) arranged in a shoulder portion of the piston skirt. The thermal strut is composed of an annular fiber-reinforced metal portion in which high-tensile-strength reinforcing fibers are integrally molded. The reinforcing fibers include first fibers (34), such as carbon fibers, having a coefficient of linear expansion substantially smaller than that of the matrix metal alloy, and second fibers (36), such as silicon carbide fibers and alumina fibers, having a flexural or bending strength larger than that of the first fibers. The first fibers primarily serve to restrain thermal expansion of the piston skirt and the second fibers, having a larger bending strength, act to protect the first fibers from excessive bending forces. In a preferred embodiment, the first fibers are located in the inner region of the thermal strut and the second fibers are arranged in the outer region.
摘要:
A stainless steel separator, which is good of corrosion-resistance and low of contact-resistance, is proposed for a fuel cell. Its surface faced to a fuel electrode is pickled, which the other surface faced to an oxidizing electrode is roughened by electrolytic etching or the like. The roughening treatment may be performed before or after pickling and passivation. The roughened surface of the stainless steel separator without pickling or passivation may be faced to the oxidizing electrode.
摘要:
A slide member is made of an aluminum alloy and compositely reinforced at its sliding surface by a reinforcing material. The reinforcing material is a mixture of alumina short fibers consisting of not less than 80 wt. % alumina and the remainder silica and having 5-60 wt. % alpha alumina content, and non-spherical mullite particles consisting of 40-86 wt. % alumina and the remainder silica and having 3-60 microns mean diameter. The volumetric percentages of the alumina short fibers and the mullite particles are 2-12% and 5-25%, respectively, on the basis of the volume of the reinforced portion.
摘要:
A metal matrix composite material having uniformly dispersed intermetallic compounds and no micropores is manufactured by forming a porous preform including 60% to 80% by volume fine fragments essentially made of aluminum, 1% to 10% by volume fine fragments essentially made of nickel, copper or both, and 1% to 10% by volume fine fragments essentially made of titanium so that these fine fragments occupy in total 62% to 95% by volume of said preform, and at least a part of the preform is contacted with a melt of a matrix metal selected from aluminum, aluminum alloy, magnesium and magnesium alloy, so that the porous preform is infiltrated with the melt under no substantial application of pressure to the melt.
摘要:
In a method for making a carbon fiber reinforced material, a mass of carbon fibers, disposed in a closed loop configuration, and initially having a Young's modulus which is between about 23 ton/mm.sup.2 (23,000 kg/mm.sup.2) and about 35 ton/mm.sup.2 (35,000 kg/mm.sup.2), is embedded within a mass of matrix metal by a process which involves the mass of matrix metal being heated at least to its melting point. A composite material made by such a method is also disclosed. Preferably, the carbon fibers, before being thus embedded in the mass of matrix metal, should have a Young's modulus which is between about 23 ton/mm.sup.2 and about 30 ton/mm.sup.2. By the Young's modulus of the carbon fibers thus being relatively moderate, the occurrence of faults such as cracks and fissures in the resulting composite material is obviated, and the resulting composite material has good strength and other characteristics.