Abstract: Herein disclosed, as a Ni-based corrosion-resistant alloy to be used for build-up welding, is an alloy which contains 0.5 to 2.3 wt % of copper, 0.1 to 5.3 wt % of molybdenum, 1.0 to 29.0 wt % of at least one carbide forming element except molybdenum, 1.0 to 30.0 wt % of iron, 0.6 to 2.5 wt % of silicon, 0.008 up to 1.0 wt % of boron, and 0.04 to 1.6 wt % of carbon, the remainder being composed of nickel and incidental impurities.

Abstract: A dispersion strengthened Cu (copper)-base alloy for a wear-resistant overlay formed on a metal substrate consists essentially of, by weight %,Ni: 5 to 30%;B: 0.5 to 3%;Si: 1 to 5%;Fe: 4 to 30%;Sn: 3 to 15% and/or An: 3 to 30%; andthe remainder being Cu and unavoidable impurities, and has a structure in which particles of boride and silicide of the Fe-Ni system are dispersed in a Cu-base matrix, and Cu-base primary crystals contain Sn and/or Zn in a solid solution state. If necessary, 0.1 to 5% of Al, 0.1 to 5% of Ti, and/or 1 to 10% of Mn may be added. 0.02 to 2% of C, and 0.1 to 10% of Cr and/or 0.3 to 5% of Ti may be further added. Instead of or along with Sn and/or Zn, 2 to 20% of Pb can be used, and nonsoluble Pb particles are uniformly dispersed between Cu-base .alpha. phase dendrites and serve as a solid lubricant.

Abstract: Herein disclosed is a process for forming a dispersion alloy layer on a metallic base. The powder of an alloy system, which will separate into two or more multi-liquid phases at a temperature equal to or higher than its melting point and will solidify, when quenched, with its individual liquid phases being separate and in which the ratio of the minimum to the maximum specific weight its individual liquid phases is 0.3 or higher, such as the powder of any alloy system of Cu-Ni(15%)-Fe(8%)-Si(3%)-B(1.5%) is applied to a metallic base. The powder thus applied is then melting and agitated while being irradiated with a laser beam oscillated. The agitated melt of the powder is then quenched to solidify with the movement of the laser beam thereby to form on the metallic base the dispersion alloy layer in which the solid particles of at least one of those phase such as silicide particles are dispersed in the matrix of the remaining one of the phases.

Abstract: Herein disclosed is a dispersion strengthened copper-base alloy having an excellent wear resistance, which alloy contains 5 to 30% (in weight) of nickel, 1 to 5% of silicon, 0.5 to 3% of boron and 4 to 30% of iron, the remainder being copper and unavoidable impurities, and having a structure in which hard particles composed chiefly of a silicide of iron-nickel system are dispersed in a copper-base matrix. The copper-base alloy is suitably cladded (or deposited) locally on a metallic base. The alloy may contain at least one of 0.1 to 5% of aluminum, 0.1 to 5% of Ti and 1 to 10% of Mn, if necessary, in addition to the above specified components. If necessary, 0.02 to 2% of carbon and 0.5 to 10% of chromium and/or 0.3 to 5% of titanium may be further added. Then, the structure is modified such that both the particles composed chiefly of the iron-nickel silicide and carbide particles are coexistently dispersed in the copper-base matrix.

Abstract: In this method for forming an alloy layer on the surface of an aluminum alloy substrate, a powder for alloying, containing a substance to be alloyed with the substrate and an element selected from the group consisting of silicon and bismuth, is disposed upon the surface of the aluminum alloy substrate. This powder is then irradiated with a CO.sub.2 laser, so as to be melted and fused together with a surface portion of the aluminum alloy substrate, so that these two are alloyed together. The powder for alloying may be a powder of an alloy of the substance to be alloyed with the aluminum alloy substrate and the element selected from the group consisting of silicon and bismuth, or alternatively may be a mixture of a powder of the substance to be alloyed with the aluminum alloy substrate and a powder of the element selected from the group consisting of silicon and bismuth.

Abstract: In a method for forming a covering composite layer on the surface of an aluminum alloy substrate, a powder mixture containing ceramic carbide of a metal, silicon and a metal element which forms with silicon an inter metallic compound having a specific gravity comparable with that of the ceramic carbide is disposed upon the surface of the aluminum alloy substrate, and then the powder mixture so disposed is irradiated with a laser, so that the silicon and the metal element which forms the inter metallic compound with silicon in the powder mixture and a surface portion of the aluminum alloy substrate are melted and fused together.

Abstract: In this method for padding, a layer of a copper type alloy material in powdered form is laid upon a portion of a base of aluminum type metal which is to be padded. Then a laser beam, concentrated to a spot from about 0.5 mm to about 2.0 mm in diameter with an output density of from about 80 watt/mm.sup.2 to about 20,000 watt/mm.sup.2, is irradiated upon this layer of powdered copper type alloy material upon the base of aluminum type metal. The laser beam and the base of aluminum type metal are relatively moved in a relative longitudinal direction at a longitudinal speed of from about 100 mm per minute to about 3000 mm per minute; and they are also reciprocatingly moved in a relative direction substantially transverse to the longitudinal direction at an transverse oscillating frequency of above about 80 Hz. Thereby, good padding efficiency is obtained.

Abstract: This internal combustion engine cylinder head includes a main portion made substantially from aluminum alloy and having a valve port which has a circumferential valve seat surface for cooperation with a poppet valve to open and close communication through the valve port. A cladding layer is formed of copper alloy claddingly laid upon this valve seat surface, and an intermediate alloy layer is present between the copper alloy cladding layer and the main cylinder head portion, this intermediate alloy layer being composed essentially of an alloy between the aluminum alloy of the main cylinder head portion and the copper alloy of the cladding layer. Thereby, the anti-wear properties of the valve seat are desirably improved without making the fabrication process unduly troublesome or costly. The proportion of aluminum diffused into the copper alloy cladding layer from the main portion of the cylinder head should preferably be not more than about 15%.