Provided is a high-temperature lead-free solder alloy having excellent tensile strength and elongation in a high-temperature environment of 250° C. In order to make the structure of an Sn—Sb—Ag—Cu solder alloy finer and cause stress applied to the solder alloy to disperse, at least one material selected from the group consisting of, in mass %, 0.003 to 1.0% of Al, 0.01 to 0.2% of Fe, and 0.005 to 0.4% of Ti is added to a solder alloy containing 35 to 40% of Sb, 8 to 25% of Ag, and 5 to 10% of Cu, with the remainder made up by Sn.

Provided is a high-temperature lead-free solder alloy having excellent tensile strength and elongation in a high-temperature environment of 250° C. In order to make the structure of an Sn—Sb—Ag—Cu solder alloy finer and cause stress applied to the solder alloy to disperse, at least one material selected from the group consisting of, in mass %, 0.003 to 1.0% of Al, 0.01 to 0.2% of Fe, and 0.005 to 0.4% of Ti is added to a solder alloy containing 35 to 40% of Sb, 8 to 25% of Ag, and 5 to 10% of Cu, with the remainder made up by Sn.

An internal combustion engine comprising: a combustion chamber surrounded by at least an inner wall of a cylinder bore, a cylinder head, a valve and a piston, and a coating layer arranged on at least part of the inner wall of the combustion chamber, wherein the thermal conductivity of the coating layer is, at room temperature, lower than the thermal conductivities of the cylinder block, the cylinder head, the valve and the piston, the thermal conductivity of the coating layer is reversibly increased along with a rise in the temperature of the coating layer, and wherein the heat capacity per unit area of the coating layer is more than 0 kJ/(m.sup.2.Math.K) and 4.2 kJ/(m.sup.2.Math.K) or less.

An internal combustion engine comprising: a combustion chamber surrounded by at least an inner wall of a cylinder bore, a cylinder head, a valve and a piston, and a coating layer arranged on at least part of the inner wall of the combustion chamber, wherein the thermal conductivity of the coating layer is, at room temperature, lower than the thermal conductivities of the cylinder block, the cylinder head, the valve and the piston, the thermal conductivity of the coating layer is reversibly increased along with a rise in the temperature of the coating layer, and wherein the heat capacity per unit area of the coating layer is more than 0 kJ/(m.sup.2.Math.K) and 4.2 kJ/(m.sup.2.Math.K) or less.

A sintered sliding material with excellent corrosion resistance, heat resistance, and wear resistance is provided. The sintered sliding material has a composition made of: 36-86 mass % of Ni; 1-11 mass % of Sn; 0.05-1.0 mass % of P; 1-9 mass % of C; and the Cu balance including inevitable impurities. The sintered sliding material is made of a sintered material of a plurality of grains of alloy of Ni—Cu alloy or Cu—Ni alloy, the Ni—Cu alloy and the Cu—Ni alloy containing Sn, P, C, and Si; has a structure in which pores are dispersedly formed in grain boundaries of the plurality of the grains of alloy; and as inevitable impurities in a matrix constituted from the grains of alloy, a C content is 0.6 mass % or less and a Si content is 0.15 mass % or less.

A sintered sliding material with excellent corrosion resistance, heat resistance, and wear resistance is provided. The sintered sliding material has a composition made of: 36-86 mass % of Ni; 1-11 mass % of Sn; 0.05-1.0 mass % of P; 1-9 mass % of C; and the Cu balance including inevitable impurities. The sintered sliding material is made of a sintered material of a plurality of grains of alloy of Ni—Cu alloy or Cu—Ni alloy, the Ni—Cu alloy and the Cu—Ni alloy containing Sn, P, C, and Si; has a structure in which pores are dispersedly formed in grain boundaries of the plurality of the grains of alloy; and as inevitable impurities in a matrix constituted from the grains of alloy, a C content is 0.6 mass % or less and a Si content is 0.15 mass % or less.

An austenitic Fe—Ni—Cr alloy comprises C: 0.005˜0.03 mass %, Si: 0.17˜1.0 mass %, Mn: not more than 2.0 mass %, P: not more than 0.030 mass %, S: not more than 0.0015 mass %, Cr: 18˜28 mass %, Ni: 21.5˜32 mass %, Mo: 0.10˜2.8 mass %, Co: 0.05˜2.0 mass %, Cu: less than 0.25 mass %, N: not more than 0.018 mass %, Al: 0.10˜1.0 mass %, Ti: 0.10˜1.0 mass %, Zr: 0.01˜0.5 mass %, and the balance being Fe and inevitable impurities; wherein Cr, Mo, N and Cu satisfy PRE=Cr+3.3×Mo+16×N≧20.0 and PREH=411-13.2×Cr-5.8×Mo+0.1×Mo.sup.2+1.2×Cu≦145.0 and wherein Al, Ti, and Zr satisfy 0.5≦Al+Ti+1.5×Zr≦1.5, and has an excellent corrosion resistance in air or under a wet environment even at a surface state having an oxide film formed by an intermediate heat treatment.

An austenitic Fe—Ni—Cr alloy comprises C: 0.005˜0.03 mass %, Si: 0.17˜1.0 mass %, Mn: not more than 2.0 mass %, P: not more than 0.030 mass %, S: not more than 0.0015 mass %, Cr: 18˜28 mass %, Ni: 21.5˜32 mass %, Mo: 0.10˜2.8 mass %, Co: 0.05˜2.0 mass %, Cu: less than 0.25 mass %, N: not more than 0.018 mass %, Al: 0.10˜1.0 mass %, Ti: 0.10˜1.0 mass %, Zr: 0.01˜0.5 mass %, and the balance being Fe and inevitable impurities; wherein Cr, Mo, N and Cu satisfy PRE=Cr+3.3×Mo+16×N≧20.0 and PREH=411-13.2×Cr-5.8×Mo+0.1×Mo.sup.2+1.2×Cu≦145.0 and wherein Al, Ti, and Zr satisfy 0.5≦Al+Ti+1.5×Zr≦1.5, and has an excellent corrosion resistance in air or under a wet environment even at a surface state having an oxide film formed by an intermediate heat treatment.

The present invention provides a method for manufacturing a curved thin-walled intermetallic compound component by winding a mandrel with metal foil strips, which comprises the following steps: designing a prefabricated blank; preparing a support mandrel; determining thicknesses and layer numbers of foil strips; determining widths of the foil strips; establishing a laying process; pretreating surfaces of the foil strips; laying A foil and B foil; carrying out bulge forming on the prefabricated blank; carrying out diffusion reaction and densification treatment on a bulged component; and carrying out subsequent treatment of a thin-walled component. The present invention can solve the problems that impurities generated in the separation process of a support mould and a laminated foil prefabricated blank influence the final performance of a part, and a single homogeneous intermetallic compound component in thickness direction has poor plasticity and toughness at room temperature.

A metallic alloy, more particularly, a high-entropy alloy with a composite structure exhibits high strength and good ductility, and is used as a component material in electromagnetic, chemical, shipbuilding, machinery, and other applications, and in extreme environments, and the like.