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SEALING OF FRICTION STIR WELDED LAP JOINTS

IP Title

METHOD AND SEALANT FOR WELD JOINTS

Detailed Technology Description

None

Supplementary Information

Patent Number: US6905060B2
Application Number: US2003692825A
Inventor: Van Aken, David C. | Baumann, John A. | Lederich, Richard J. | Talwar, Rajesh
Priority Date: 24 Oct 2003
Priority Number: US6905060B2
Application Date: 24 Oct 2003
Publication Date: 14 Jun 2005
IPC Current: B23K002012 | B23K003528 | B23K003530
US Class: 2281121 | 2280021 | 228199
Assignee Applicant: The Boeing Company,Chicago | The Curators of the University of Missourilumbia
Title: Method and sealant for weld joints
Usefulness: Method and sealant for weld joints
Summary: For weld joining structural members.
Novelty: Weld joint for structural members, has sealant having aluminum and germanium with melting temperature lower than melting temperature of structural members

Industry

Architecture/Construction

Sub Category

Construction Engineering

Application Date

Oct 24, 2003

Application No.

6,905,060

Others

*Abstract

Abstract of US Patent 6,905,060 - Method and sealant for weld jointsA sealant for a weld joint and an associated weld joint and method are provided. The sealant includes aluminum and germanium and is characterized by a melting temperature that is lower than the melting temperature of the structural member that is joined. The sealant, which is disposed between faying surfaces of the structural members, can fill the spaces between the structural members to prevent the entry of chemicals, moisture, debris, and other substances, thereby reducing the likelihood of corrosion of the joint or structural members at the interface. Further, the sealant can be diffusion bonded to the faying surfaces, for example, by the heat generated during the joining process.Non-confidential Abstract of Invention: To seal a lap joint during friction stir welding, a coating of an Al-Ge (Aluminum-Germanium) based interface alloy (sealant) is applied to the faying surfaces of the joint using air plasma spraying or similar technique. The composition of the coating can range from 10 weight percent to 51.6 weight percent Ge with the remainder being Al. During friction stir welding, a peak temperature of around 500°C occurs close to the friction stir welding tool. The solidus temperature of the Al-Ge sealant is 420°C. So during friction stir welding the sealant melts and diffuses into the joining members thus creating a metallurgical seal on both sides of the weld nugget. The interface alloy applied on the faying surfaces of the joint should be cathodic with respect to the aluminum alloys; otherwise, galvanic corrosion of the lap joint will occur. The only viable alloys that can be used as sealant are based on Al-Ge (420°C), Al-Ge-Si (>420°C) and Al-Ag-Ge (418°C), (melting temperatures in the bracket). Sr is added in quantities less than 0.5wt. % to modify or refine the Ge.

*IP Issue Date

Jun 14, 2005

*IP Publication Date

Apr 28, 2005

*Principal Investigator

Name: David Van Aken

Department:

Name: John Baumann

Department:

Name: Richard Lederich

Department:

Name: Rajesh Talwar

Department:

Country/Region

USA