A production method for a high-strength steel sheet having a tensile strength TS of 780 MPa or more is provided. The production method comprises: heating a steel slab having a predetermined chemical composition; hotrolling the steel slab; coiling the hot-rolled sheet; subjecting the hot-rolled sheet to pickling treatment; holding the hot-rolled sheet in a pre-determined temperature range for predetermined time; cold rolling the hot-rolled sheet to obtain a cold-rolled sheet; subjecting the cold-rolled sheet to first annealing treatment; cooling the cold-rolled sheet at a pre-determined average cooling rate; cooling the cold-rolled sheet to room temperature; reheating the clod-rolled sheet to perform second annealing treatment; cooling the cold-rolled sheet at a first average cooling rate; cooling the cold-rolled sheet at a second average cooling rate; reheating the cold-rolled sheet to a predetermined reheating temperature range; and holding the cold-rolled sheet in the reheating temperature range.

A composite metal foil and a preparation method thereof are provided. The composite metal foil includes a carrier layer, a barrier layer, a striping layer, and a metal foil layer. The carrier layer, the barrier layer, the striping layer, and the metal foil layer are sequentially stacked, the barrier layer includes a metal bonding layer and a high-temperature resistant layer stacked, and the metal bonding layer is disposed between the carrier layer and the high-temperature resistant layer. The striping layer is disposed between the carrier layer and the metal foil layer so as to facilitate peeling of the carrier layer, and the barrier layer is disposed between the carrier layer and the metal foil layer so as to prevent the carrier layer and the metal foil layer from diffusing mutually to cause bonding at a high temperature, so that the carrier layer and the metal foil layer are easy to peel off. In addition, the metal bonding layer is disposed between the carrier layer and the high-temperature resistant layer, so that the barrier layer is not easy to separate from the carrier layer, and peeling between the barrier layer and the carrier layer is prevented.

A composite metal foil and a preparation method thereof are provided. The composite metal foil includes a carrier layer, a barrier layer, a striping layer, and a metal foil layer. The carrier layer, the barrier layer, the striping layer, and the metal foil layer are sequentially stacked, the barrier layer includes a metal bonding layer and a high-temperature resistant layer stacked, and the metal bonding layer is disposed between the carrier layer and the high-temperature resistant layer. The striping layer is disposed between the carrier layer and the metal foil layer so as to facilitate peeling of the carrier layer, and the barrier layer is disposed between the carrier layer and the metal foil layer so as to prevent the carrier layer and the metal foil layer from diffusing mutually to cause bonding at a high temperature, so that the carrier layer and the metal foil layer are easy to peel off. In addition, the metal bonding layer is disposed between the carrier layer and the high-temperature resistant layer, so that the barrier layer is not easy to separate from the carrier layer, and peeling between the barrier layer and the carrier layer is prevented.

In a layered bonding material 10, a coefficient of linear expansion of a base material 11 is 5.5 to 15.5 ppm/K and a first surface and a second surface of the base material 11 are coated with pieces of lead-free solder 12a and 12b.

In a layered bonding material 10, a coefficient of linear expansion of a base material 11 is 5.5 to 15.5 ppm/K and a first surface and a second surface of the base material 11 are coated with pieces of lead-free solder 12a and 12b.

A hot stamped component, includes: a base material; and a Zn-based plating layer provided in contact with the base material as an upper layer of the base material and containing Zn and Ni. A region of the Zn-based plating layer on a base material side is a Fe—Zn solid solution containing Ni, and two or more twins exist in 10 crystal grains of the Fe—Zn solid solution containing Ni adjacent to an interface between the base material and the Zn-based plating layer.

A ceramic circuit board includes a ceramic base material, a metal layer (first metal layer), and a marker portion. The marker portion is formed on the surface of the first metal layer. The surface of the metal layer (first metal layer) may be plated. When the surface of the metal layer (first metal layer) is plated, the marker portion may be formed on the plating.

The heat-dissipating substrate structure includes a base layer and a cold spray coating layer. The cold spray coating layer is formed on a surface of the base layer. The cold spray coating layer is a film formed on the surface of the base layer by spraying a solid-phase metal powder and a high-pressure compressed gas onto the base layer. The solid-phase metal powder at least includes a film-forming powder with an apparent density of 3 to 4 g/cm.sup.3 and a median particle diameter (D50) of 30 μm or less. A maximum depth of a bottom of the cold spray coating layer embedded in the base layer is less than 60 μm. A cooler contains an internal cooling fin joined to the base layer. An internal coolant passage is defined between the base layer, the internal cooling fin, and an interior of the cooler.

[Problem] To provide: a roll-bonded body which is able to be suppressed in waviness in the surface; and a method for producing this roll-bonded body. [Solution] A roll-bonded body according to the present invention is obtained by bonding a first metal layer and a second metal layer with each other by means of rolling, and is characterized in that the surface of the first metal layer has an arithmetic average waviness (Wa.sub.1) 0.01-0.96 and a maximum waviness height (Wz.sub.1) of 0.2-5.0 μm.

[Problem] To provide: a roll-bonded body which is able to be suppressed in waviness in the surface; and a method for producing this roll-bonded body. [Solution] A roll-bonded body according to the present invention is obtained by bonding a first metal layer and a second metal layer with each other by means of rolling, and is characterized in that the surface of the first metal layer has an arithmetic average waviness (Wa.sub.1) 0.01-0.96 and a maximum waviness height (Wz.sub.1) of 0.2-5.0 μm.