Abstract: A method is disclosed for improving the corrosion behavior of cast magnesium alloy articles in which the magnesium alloy comprises an average composition of more than about 5 per cent by weight of aluminum. A microstructure with regions of varying aluminum content is developed during solidification. The microstructure comprises magnesium-rich grains generally surrounded by an aluminum-enriched phase on the boundaries between adjacent grains. The magnesium-rich grain interiors are then selectively chemically or electrochemically attacked to leave a more corrosion resistant aluminum-enriched surface on the articles. The corrosion resistance of the articles may be further enhanced by one or more of anodizing, aluminizing or painting the corrosion-resistant aluminum-enriched surface.

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: The geometric stiffness of structural sheet metal panels, such as those employed in motor vehicles, may be increased, without major increase in the mass of the panel, by application of a coating of a structural polymer. However conventional means of applying such a polymer layer require multiple applications to achieve a desired thickness. By incorporating magnetic particles in a resin, and subjecting the resin to a magnetic field as it is applied, the desired thickness may be achieved in a single application. Embodiments appropriate to the application of such a resin to both magnetic and non-magnetic materials are described.

Abstract: Unitary closure panels for automotive vehicles may be formed to have regions of different materials by a spray casting process. Separate sprays of different materials, for example two different metal alloys, are applied to touching regions of a spray application surface. The separate sprays may be applied sequentially or simultaneously to the forming surface to coat the respective regions so that the regions are contiguous or overlapping and a unitary body is formed. The spray formed body may be compressed and trimmed between facing surfaces to form a vehicle closure panel of specified outline, curvature, thickness, and porosity.

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 improving the corrosion behavior of cast magnesium alloy articles in which the magnesium alloy comprises an average composition of more than about 5 per cent by weight of aluminum. A microstructure with regions of varying aluminum content is developed during solidification. The microstructure comprises magnesium-rich grains generally surrounded by an aluminum-enriched phase on the boundaries between adjacent grains The magnesium-rich grain interiors are then selectively chemically or electrochemically attacked to leave a more corrosion resistant aluminum-enriched surface on the articles. The corrosion resistance of the articles may be further enhanced by one or more of anodizing, aluminizing or painting the corrosion-resistant aluminum-enriched surface.

Abstract: Unitary closure panels for automotive vehicles may be formed to have regions of different materials by a spray casting process. Separate sprays of different materials, for example two different metal alloys, are applied to touching regions of a spray application surface. The separate sprays may be applied sequentially or simultaneously to the forming surface to coat the respective regions so that the regions are contiguous or overlapping and a unitary body is formed. The spray formed body may be compressed and trimmed between facing surfaces to form a vehicle closure panel of specified outline, curvature, thickness, and porosity.

Abstract: A magnesium alloy comprising up to about one weight percent of cerium may be hot worked to produce an intermediate or final alloy workpiece that exhibits enhanced ductility at room temperature. The addition of a small amount of cerium may affect the magnesium alloy by reducing yield strength, refining grain size, and improving the work hardening behavior. Recrystallization during hot deformation of the rare earth containing magnesium material alters the texture of the alloy and orients the grains in a manner that favors basal slip activity. The alloy thus deforms at room temperature by a combination of twinning and slip mechanisms.