摘要:
A major engine casting, such as an engine block or a cylinder head, fabricated of either magnesium or aluminum alloy, has a cast-in-place metal tube or form embedded within it. The tube or form enables circulation of liquid while substantially physically isolating the casting alloy from the circulating liquid and thereby restricting or eliminating corrosive interaction between them.
摘要:
A linerless engine includes a casting defining a bore having an inner surface and a central longitudinal axis. The casting is formed from a castable aluminum-silicon alloy including silicon particles present a range of from about 11 to about 12.5 parts by weight. The inner surface has a surface variation defined by at least some of the silicon particles protruding toward the axis for from about 0.6 to about 1.5 microns. The linerless engine includes a piston slideably disposed within the bore and configured for translating along the axis, wherein the piston is formed from an aluminum alloy and includes a body having a skirt portion coated with a first coating, and at least one ring encircling and in contact with the body. The ring is coated with a diamond-like coating that is free from degradation when in contact with the at least some of the silicon particles.
摘要:
Some die cast aluminum alloy articles have internal cylindrical surfaces such as the round internal cylinder surfaces of a cylinder block for an internal combustion engine. During casting solidification molten aluminum alloys shrink against the metallic permanent mold tools used to mold and define such internal surfaces, and tend to stick to the tool surfaces making it difficult to remove the casting. The tendency of some aluminum casting alloys to solder to the tool can further intensify sticking. In this invention, an aluminum alloy sleeve is placed on and over the tool surface before casting and the sleeve isolates the tool from the molten aluminum. The sleeve becomes bonded to the casting and facilitates removal of the casting from the tool. The sleeve may be (and preferably is) fully machined from the internal casting surface. The sleeve may be of the same composition as the casting, in which case handling and recycling of machining chips would be facilitated. The practice of the invention is also applicable to die casting of magnesium alloys using magnesium sacrificial sleeves.
摘要:
A method of bonding a metal to a substrate involves forming an oxide layer on a surface of the substrate, and in a molten state, over-casting the metal on the substrate surface. The over-casting drives a reaction at an interface between the over-cast metal and the oxide layer to form another oxide. The other oxide binds the metal to the substrate surface upon solidification of the over-cast metal.
摘要:
A method of forming a coated article is disclosed. The method involves heating a magnesium alloy component, positioning the component in a mold such that a gap exists between component outer surfaces and mold inner surfaces, and heating a magnesium-containing alloy material above its melting temperature, which is lower than that of the component. The material is formed from magnesium alloyed with i) the component element, but at a higher concentration, ii) at least one element that is different than the component element, or iii) the component element and at least one other element. The method further includes introducing the material into the gap, thereby covering at least the outer surfaces of the component, and cooling the material to form a substantially evenly distributed solidified coating on the outer surfaces of the component. The coating has a higher wear and/or corrosion resistance than that of the magnesium alloy component.
摘要:
A component includes a cast portion and an insert. The cast portion includes a sacrificial suspension device. The insert is configured to provide damping to the component. The sacrificial suspension device is dissolved during a casting process, into a molten material, forming the cast portion such that the insert is fully encapsulated by the cast portion, including the dissolved suspension device.
摘要:
A method of bonding a metal to a substrate is disclosed herein. The method involves forming a nano-brush on a surface of the substrate, where the nano-brush includes a plurality of nano-wires extending above the substrate surface. In a molten state, the metal is introduced onto the substrate surface, and the metal surrounds the nano-wires. Upon cooling, the metal surrounding the nano-wires solidifies, and during the solidifying, at least a mechanical interlock is formed between the metal and the substrate.
摘要:
A method of bonding a metal to a substrate involves forming a plurality of nano-features in a surface of the substrate, where each nano-feature is chosen from a nano-pore and/or a nano-crevice. In a molten state, the metal is over-cast onto the substrate surface, and penetrates the nano-features. Upon cooling, the metal is solidified inside the nano-features, where the solidification of the metal forms a mechanical interlock between the over-cast metal and the substrate.
摘要:
A system and method for predicting fatigue life in metal alloys for very high cycle fatigue applications. The system and method are especially useful for cast metal alloys, such as cast aluminum alloys, where a fatigue endurance limit is either non-existent or hard to discern. Fatigue properties, such as fatigue strength in the very high cycle fatigue region, are based on a modified random fatigue limit model, where the very high cycle fatigue strength and infinite life fatigue strength are refined to take into consideration the sizes of the discontinuities and microstructure constituents since the fatigue life scatter depends upon the presence of discontinuities and microstructure constituents. The sizes of the discontinuities and microstructure constituents that can initiate fatigue cracks can be determined with extreme value statistics, then input to the modified random fatigue limit model.