Bonding method of dissimilar materials made from metals and bonding structure thereof

• US 8,507,825 B2
• Filed: 09/29/2011
• Issued: 08/13/2013
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Miyamoto, Kenji, Nakagawa, Shigeyuki
• Primary Examiner(s): JENNISON, BRIAN W
• Application Number:
  US13/248,141
• Publication Number:
  US 20120021239A1
• Time in Patent Office: 684 Days
• Field of Search: 219/78.01, 219/86.1, 219/91.2, 219/91.22, 219/117.1, 219/118
• US Class Current: 219/118
• CPC Class Codes: B23K 11/115 by means of two electrodes placed opposite one another on both sides of the welded parts
• CPC Class Codes: B23K 11/20 of different metals
• CPC Class Codes: B23K 2103/20 Ferrous alloys and aluminium or alloys thereof
• CPC Class Codes: Y10T 428/12028 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
• CPC Class Codes: Y10T 428/12389 having variation in thickness
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

Disclosed is a bonding method for dissimilar materials made from metals and its resulting structures. The materials to be bonded are formed by layering three or more sheets such that a dissimilar material interface and a same material interface are formed. A first current is conducted between a three-sheet layered plate material wherein an aluminum alloy plate, a zinc plated steel plate and a bare steel plate, for example, are layered in order. A nugget is formed in an interface between the zinc plated steel plate and the bare steel plate, which are the same materials. Then, a second current greater than the first current is conducted, and a nugget is formed in an interface between the aluminum alloy plate and the zinc plated steel plate.

Claims

1. A bonded structure of dissimilar materials made from metals, comprising:

at least two plate layers of a steel material;

a plate layer of a second metallic material having a melting point lower than the steel material;

a dissimilar material interface between a plate layer of the steel material and the plate layer of the second metallic material;

a steel material interface between adjacent plate layers of the steel material, wherein a contact resistance in the dissimilar material interface is lower than a contact resistance in the steel material interface;

a first nugget formed in the dissimilar material interface to bond the plate layer of the steel material and the plate layer of the second metallic material, the first nugget having a first diameter Dd; and

a second nugget formed in the steel material interface to bond the adjacent plate layers of the steel material, the second nugget having a second diameter Ds, wherein the first diameter Dd is larger than the second diameter Ds.

2. The bonded structure according to claim 1 wherein the first diameter Dd is within a range of 4.4·

t1<

Dd<

12·

t1, with t1 being a thickness of one of the plate layers forming the dissimilar material interface that has a smaller product; and

wherein the second diameter Ds is within a range of 4√

t2<

Ds<

7√

t2, with t2 being a thickness of one of the plate layers forming the steel material interface that has a smaller product; and

wherein a product of a respective plate layer is defined as a strength per unit area multiplied by a thickness of the respective plate layer.

3. A vehicular component comprising the bonded structure of claim 2.

4. The bonded structure according to claim 1, wherein the second metallic material is an aluminum alloy.

5. The bonded structure according to claim 1, wherein the second metallic material is a magnesium alloy.

6. The bonded structure according to claim 1 further comprising:

a discharge layer around at least a portion of the nugget formed in the dissimilar material interface having the first diameter Dd.

7. The bonded structure according to claim 6, wherein the discharge layer includes fusion eutectic metal.

8. The bonded structure according to claim 6, wherein the discharge layer includes oxide coating.