Bonding structure of aluminum member and copper member

1. A bonding structure comprising:

an aluminum member composed of aluminum or an aluminum alloy;

a copper member composed of copper or a copper alloy;

an intermetallic compound layer that is made of copper and aluminum and is formed in a bonding interface between the aluminum member and the copper member; and

an oxide dispersed in an interface between the copper member and the intermetallic compound layer in a layered form along the interface,

wherein

the aluminum member and the copper member are bonded together by solid phase diffusion bonding,

wherein the intermetallic compound layer has a structure in which a plurality of intermetallic compounds is laminated along the bonding interface,

wherein the intermetallic compound layer has a structure in which a θ phase, a η2 phase, and at least one phase selected from a group consisting of a ζ2 phase, an δ phase, and a γ2 phase are laminated,

wherein the θ phase, the η2 phase, and the at least one phase selected from the group consisting of the ζ2 phase, the δ phase, and the γ2 phase are laminated sequentially from the aluminum member toward the copper member,

wherein an average crystal grain size of the copper member is in a range of 80 μm to 180 μm in the vicinity of the bonding interface, and

wherein an average crystal grain size of the aluminum member is 500 μm or more in the vicinity of the bonding interface.

2. The bonding structure according to claim 1 , wherein the oxide is dispersed in a state of being divided in the interface between the copper member and the intermetallic compound layer, and the copper member and the intermetallic compound layer are partially in contact with each other.

3. The bonding structure according to claim 1 , wherein an oxide is dispersed in a layered form inside a layer configured of the at least one phase selected from the group consisting of the ζ2 phase, the δ phase, and the γ2 phase.