Abstract: A system may be used to detect corrosion between a first metal and a second metal, where the second metal is positioned adjacent to the first metal. The system may include a processor electrically coupled to each of the first and the second metals and configured to monitor a complex impedance between the first metal and the second metal, where the complex impedance may include a real component and an imaginary component. The processor may compare the real component of the complex impedance to a first threshold, compare the imaginary component of the complex impedance to a second threshold, and indicate a likelihood of corrosion if at least one of the real and imaginary components are below their respective threshold.

Abstract: A method is disclosed for forming corrosion-resistant joints in a plurality of overlapping thin metal sheet workpieces, at least one of which comprises at least 85% by weight of magnesium sheets. The fastener is a fiber-reinforced polymer rod shaped and sized for insertion into a coaxial opening formed in each sheet and subsequently upset on each end to form a head. The workpiece sheets are deformed to form mechanically-interfering features which cooperatively complement the strength of the fastener, under at least some joint loading patterns. The method may be used for other workpiece and fastener compositions.

Abstract: A method of enhancing the ductility of magnesium alloy sheets containing 85% or more by weight of magnesium is described. An annealed, substantially strain free, sheet of generally uniform grain size is locally deformed in local regions to develop strained ‘islands’ of a predetermined strain embedded in a substantially strain-free matrix and then annealed. The deformed regions undergo recrystallization and grain growth while the remainder of the sheet suffers only minor change in grain size, leading to sheet with grains having a bimodal size distribution. The ductility of alloys processed in this way is significantly greater than the ductility of the unprocessed, uniform grain size alloy without compromise to the tensile strength of the alloy.

Abstract: The corrosion resistance of formed and shaped sheet magnesium alloy articles may be improved by applying to the article a substantially crack-and pore-free ductile metal layer on at least selected surfaces and cut or sheared edges. An exemplary ductile metal may be aluminum or its alloys. Two methods of applying such a ductile metal layer are described. One method is suitable for extended areas of the magnesium alloy sheet surface, and is applied prior to stamping the article, while a second method, suitable for cut or sheared edges, is intended for application after the article is fully formed. The incorporation of both methods into conventional sheet metal stamping processes to form the corrosion resistant formed magnesium article is described.

Abstract: Methods of joining a magnesium substrate to a second substrate are provided. A region of the magnesium substrate and a region of the second substrate are aligned to provide an overlap. A region of the overlap is deformed to provide a joint. A polymeric material is disposed in the joint to secure together the magnesium substrate and the second substrate. The joining of the magnesium substrate and the second substrate is facilitated by using a die in various aspects.

Abstract: A method of forming an article from a metal alloy sheet material includes selectively hardening only a first localized area of the metal alloy sheet material without hardening a second localized area of the metal alloy sheet material, wherein the second area adjoins the first area to thereby form a blank. The blank has a hardened region formed from the first area and having a first hardness, and a non-hardened region adjoining the hardened region and formed from the second area, and having a second hardness that is less than the first hardness. The method includes stamping the blank to thereby form a preform having a pre-protrusion at least partially formed from the hardened region, wherein the pre-protrusion has a first height, annealing the preform to thereby form a workpiece, and stamping the workpiece to increase the first height and thereby form the article.

Abstract: A method for forming an aperture includes stamping an aperture into the article using a pellet, and refining aperture shape(s) and/or aperture dimensions. Methods for forming articles having reduced residual compressive stress are also disclosed. Very generally, the methods include establishing a diamond coating on at least a portion of a substrate, and applying a stress-relief process to the diamond coating, the substrate, or combinations thereof.

Abstract: The formability of coiled and annealed (O-temper) magnesium alloy sheet material in high temperature forming operations is sometimes adversely affected by small amounts of cold work introduced into the fine grained material during handling of the coil and unwinding it to obtain blank workpieces for hot stamping, hot blow forming, or the like. When necessary, the formability of the sheet material with regions of hard worked microstructure may be improved by predetermining a recovery heat treatment using small portions of the material in formability tests. The recovery heat treatment, determined for the specific coiled stock, may then be applied to the material of the coil as it is used in making vehicle body panels or the like.

Abstract: A method of forming an article from a metal alloy sheet material includes stamping the metal alloy sheet material to thereby form a preform having at least one protrusion. The at least one protrusion includes a base portion, a first region having a first thickness and spaced apart from the base portion to thereby have a first maximum height, and a second region interconnecting the base portion and the first region and having a second thickness that is greater than the first thickness. After stamping, the method includes selectively annealing the second region without substantially annealing the first region, and, after selectively annealing, concurrently increasing the first maximum height and substantially equalizing the first thickness and the second thickness to thereby form the article.

Abstract: A clinching method includes establishing a first layer on a second layer. The first layer has an aperture formed therein and is thinner than the second layer. A rotating punch is engaged with the second layer through the aperture in the first layer, thereby generating frictional heat and softening the second layer. The rotating punch is configured with at least a first diameter, a shoulder, and a second diameter that is larger than the first diameter. The rotating punch is pressed into the softened second layer, thereby causing at least some of the second layer to: back extrude through an annulus defined by the aperture in the first layer and at least one of the diameters of the punch; contact the shoulder of the rotating punch; and extend onto a surface of the first layer adjacent the aperture.

Abstract: A first layer is established on a second layer and an induction coil is disposed within induction proximity to the second layer. The induction coil is electrically energized thereby heating the second layer to a target temperature. A die having a die cavity is translated from a first location spaced substantially beyond an induction heating distance from the induction coil to a clamping location adjacent the second layer such that the induction coil surrounds a predetermined location on an external surface of the die. The die is heated by induction between the induction coil and the die while the die is translated toward the clamping location until the die reaches a predetermined die temperature. The induction coil is de-energized after the die has reached the predetermined die temperature. The first layer and the second layer are clamped between a binder and the die.

Abstract: A replaceable deformable insert is disposed in a clinching die cavity having an annular recess adjacent the insert. A first layer is established on a second layer and secured between a retractable punch and the clinching die. The punch is pressed into the first layer to form a depression in the first and second layers. The first and second layers are compressed together between the punch and the clinching die, creating hydrostatic pressure in the first and second layers and the insert. A portion of the insert is extruded to fill the annular recess with insert extrudate, while a portion of the second layer is simultaneously radially extruded into an annular space previously occupied by the insert. A portion of the first layer is simultaneously radially extruded into an annular volume previously occupied by the second layer, thereby forming an interlocking assembly of the first and second layers and insert.

Abstract: A magnesium alloy panel for a vehicle includes a first region and a second region extending from the first region to an edge. The first region has a first microstructure having a first corrosion resistance. The second region has a second microstructure different than the first microstructure and has a second corrosion resistance greater than the first corrosion resistance. A system for mass producing magnesium alloy panels includes a forming apparatus and a laser cutting apparatus. The forming apparatus forms a panel having a first microstructure having a first corrosion resistance. The laser cutting apparatus cuts the panel to form the edge using a laser, and forms the second microstructure while forming the edge. The second microstructure is different than the first microstructure and has a second corrosion resistance greater than the first corrosion resistance. A method for mass producing magnesium alloy panels is also provided.

Abstract: A tubular support member includes a plurality of undulations extending along a longitudinal axis of the tubular support member and angularly spaced about the longitudinal axis. The undulations form a plurality of alternating peaks and valleys in the tubular support member. A cast member is overcast from a molten metal onto and around the undulations in interlocking engagement with the undulations, and extends from the tubular support member to a cantilevered distal end.

Abstract: A system may be used to detect corrosion between a first metal and a second metal, where the second metal is positioned adjacent to the first metal. The system may include a processor electrically coupled to each of the first and the second metals and configured to monitor a complex impedance between the first metal and the second metal, where the complex impedance may include a real component and an imaginary component. The processor may compare the real component of the complex impedance to a first threshold, compare the imaginary component of the complex impedance to a second threshold, and indicate a likelihood of corrosion if at least one of the real and imaginary components are below their respective threshold.

Abstract: An inner body panel for a vehicle, e.g., an inner panel for a trunk lid assembly, is manufactured from a magnesium alloy, and includes an abrasively rounded edge surface along an edge of the panel. The rounded edge surface includes a radius that is equal to one half the thickness of the inner panel. The rounded edge surface allows for a uniform deposition of a corrosion resistant coating along the edge of the panel.

Abstract: A method of manufacturing a closure assembly for a vehicle includes trimming an outer panel to define a first edge and trimming an inner panel to define a second edge, wherein the outer panel is formed from an aluminum alloy material and the inner panel is formed from a magnesium alloy material. The method further includes chemically shaping the second edge to define a substantially rounded edge surface having a radius, positioning the inner panel adjacent the outer panel such that the first edge extends beyond the substantially rounded edge surface, and bending the first edge of the outer panel around the substantially rounded edge surface of the inner panel to form a hem connection that secures the inner panel relative to the outer panel. A closure assembly is also disclosed.

Abstract: A method is disclosed for forming corrosion-resistant joints in a plurality of overlapping thin metal sheet workpieces, at least one of which comprises at least 85% by weight of magnesium sheets. The fastener is a fiber-reinforced polymer rod shaped and sized for insertion into a coaxial opening formed in each sheet and subsequently upset on each end to form a head. The workpiece sheets are deformed to form mechanically-interfering features which cooperatively complement the strength of the fastener, under at least some joint loading patterns. The method may be used for other workpiece and fastener compositions.

Abstract: A double-action clinching tool includes a support having an aperture formed therein and a surface configured to receive a first layer overlapping a second layer. A clinching punch is slidably positioned in the support aperture and configured to engage the second layer. A punch is positioned opposite to the clinching punch and is configured to form an aperture in the first layer prior to the clinching punch engaging the second layer. A retractable clinching die configured to contact the first layer and to shift such that an interior wall thereof is angularly offset from an initial position when contacted by a portion of the second layer extending through the aperture of the first layer.

Abstract: The invention provides a method for manufacturing an automotive component member, including the steps of: (A) positioning at least one insert into a mold, wherein the insert defines a plurality of holes; and (B) casting a portion of the automotive component member in the mold to substantially encapsulate the insert such that a major portion of the insert is substantially non-bonded with the casting material to provide a proper interfacial boundary with the casting material for damping. The method may include the step of coating the insert to prevent bonding between the insert and the casting material. A damped automotive component member having an insert cast therein is also disclosed.