# US 8,464,926 B2 · Method of friction stir welding dissimilar metals and workpiece assemblies formed thereby > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,464,926 B2 - Document ID: US8464926B2 - Status: Granted - Kind: B2 - Application number: 12/589,948 - Filed: 2009-10-30 - Published: 2011-05-05 - Granted: 2013-06-18 - Earliest claimed: 2009-10-30 - Assignees: Wisconsin Alumni Research Foundation - Applicants: Sindo Kou; Vahid Firouzdor - Inventors: Sindo Kou; Vahid Firouzdor - Web page: https://patentgrep.com/patent/US8464926B2 ## CPC - B23K 20/1265: {Non-butt welded joints, e.g. overlap-joints, T-joints or spot welds} - B23K 20/128: {making use of additional material} - B32B 7/05: the layers not being connected over the whole surface, e.g. discontinuous connection or patterned connection (using interposed adhesives or bonding materials applied in spaced arrangements B32B7/14) - B32B 15/017: {one layer being formed of aluminium or an aluminium alloy, another layer being formed of an alloy based on a non ferrous metal other than aluminium} - C22C 21/08: with silicon - C22C 23/02: with aluminium as the next major constituent - B23K 2101/185: {Tailored blanks} - B23K 2103/10: Aluminium or alloys thereof - B23K 2103/12: Copper or alloys thereof - B23K 2103/14: Titanium or alloys thereof - B23K 2103/15: {Magnesium or alloys thereof} - B23K 2103/18: Dissimilar materials - B23K 2103/20: Ferrous alloys and aluminium or alloys thereof - B23K 2103/24: Ferrous alloys and titanium or alloys thereof - Y10T 428/12347: Plural layers discontinuously bonded [e.g., spot-weld, mechanical fastener, etc.] - Y10T 428/12493: Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] - Y10T 428/12729: Group IIA metal-base component - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - C22C: ALLOYS (treatment of alloys C21D, C22F) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract In a process for friction stir welding together pieces of dissimilar material, a first piece of a second metal is overlaid onto a first piece of a first metal that is dissimilar from the second metal such that at least a portion of the first piece of second metal overlaps a portion of the first piece of first metal. A second piece of the first metal is placed in side-to-side relationship with the first piece of second metal and overlies another portion of the first piece of first metal. The relative arrangement between the second piece of first metal and the first piece of second metal define a joint line overlying the first piece of first metal. The first piece of first metal, the first piece of second metal, and the second piece of first metal are friction stir welded together along the joint line. ## Claims ### Claim 1 A workpiece assembly comprising: a first piece of a first metal; a first piece of a second metal overlying at least a portion of the first piece of first metal; a second piece of the first metal overlying the first piece of first metal and in side-to-side relationship with the first piece of second metal; and a weld seam securely joining the first piece of first metal, the first piece of second metal, and the second piece of first metal together, the weld seam being defined by a stirred mixture of the first metal and the second metal and extending between the first piece of second metal and the second piece of first metal, wherein the first metal is dissimilar from the second metal, and wherein the weld seam does not extend through the first piece of the first metal. ### Claim 2 (depends on 1) The workpiece assembly of claim 1 wherein the weld seam is offset toward the second piece of first metal. ### Claim 3 (depends on 1) The workpiece assembly of claim 1 wherein the first metal is a first metal alloy and the second metal is a second metal alloy that is dissimilar from the first metal alloy. ### Claim 4 (depends on 3) The workpiece assembly of claim 3 wherein the first metal is a magnesium alloy and the second metal is an aluminum alloy. ### Claim 5 (depends on 4) The workpiece assembly of claim 4 wherein the weld seam is defined by a stirred mixture of magnesium and aluminum alloys. ### Claim 6 (depends on 1) The workpiece assembly of claim 1 wherein the second piece of the first metal has a width that is substantially less than a width of the first piece of the first metal. ### Claim 7 (depends on 6) The workpiece assembly of claim 6 wherein the width of the second piece of the first metal is substantially less than a width of the first piece of the second metal. ### Claim 8 (depends on 1) The workpiece assembly of claim 1 further comprising a second piece of the second metal, a second piece of the second metal overlying the first piece of second metal and in side-to-side relationship with the first piece of first metal, and a second weld seam securely joining the first piece of first metal, the first piece of second metal, and the second piece of second metal together. ### Claim 9 (depends on 8) The workpiece assembly of claim 8 wherein the second weld seam is defined by a stirred mixture of the first metal and the second metal and extends between the first piece of second metal and the second piece of first metal. ### Claim 10 (depends on 8) The workpiece assembly of claim 8 wherein the second weld seam is defined by a lap weld. ### Claim 11 (depends on 1) The workpiece assembly of claim 1 wherein the first piece of the first metal has a thickness and the first piece of the second metal has a thickness, the total thickness of the workpiece assembly being equal to the sum of the thickness of the first piece of the first metal and the thickness of the first piece of the second metal. ### Claim 12 (depends on 1) The workpiece assembly of claim 1 wherein a portion of the weld seam securely joins the second piece of the first metal and the first piece of the second metal, this portion of the weld seam being visible for inspection. ### Claim 13 (depends on 1) The workpiece assembly of claim 1 wherein the weld seam has a strength of about 2,700 Newtons. ### Claim 14 (depends on 8) The workpiece assembly of claim 8 wherein the weld seam and the second weld seam have a combined strength between about 3,550 Newtons and about 4,530 Newtons. ### Claim 15 (depends on 1) The workpiece assembly of claim 1 wherein the weld seam is generally straight.