Abstract: Thermally activated devices, including thermally activated release devices. These devices may be used as part of any device or system in which thermal activation may be desired. In particular, described herein are thermally activated devices configured as sprinkler valves. The thermally activated devices typically include a channel and a plug element, where the plug element is a shape memory material, which may be a single-crystal shape memory alloy. The channel has two connected regions, where the first region has a diameter that is greater than the diameter of a plug element in a first configuration and the second region has a diameter that is less than the diameter of the plug element in the first configuration but greater than the diameter of the plug element in its second configuration.

Abstract: A method of manufacturing three-dimensional thin-film nitinol (NiTi) devices includes: depositing multiple layers of nitinol and sacrificial material on a substrate. A three-dimensional thin-film nitinol device may include a first layer of nitinol and a second layer of nitinol bonded to the first layer at an area masked and not covered by the sacrificial material during deposition of the second layer.

Abstract: Devices and methods fabricating devices having nanostructures that allow adhesion or growth of one cell type, such as endothelial cells, more than another cell type, such as smooth muscle cells. In particular, stent covers may have nanostructures that allow adhesion or growth of one cell type more than another cell type. Nanostructures forming the devices may be optimized.

Abstract: Dental archwires of single-crystal shape memory alloys, methods of fabrication and apparatus for fabrication. A dental archwire is provided of a hyperelastic, single-crystal shape memory CuAlX alloy, where X is Ni, Mn, Nb, or Be. The dental archwire has a shape-set curved length and either a round diameter of between about 0.013 to about 0.026 inches or a rectangular cross-section with dimensions of between about 0.016 by 0.016 inches and about 0.020 by 0.030 inches.

Abstract: A method of manufacturing three-dimensional thin-film nitinol (NiTi) devices includes: depositing multiple layers of nitinol and sacrificial material on a substrate. A three-dimensional thin-film nitinol device may include a first layer of nitinol and a second layer of nitinol bonded to the first layer at an area masked and not covered by the sacrificial material during deposition of the second layer.

Abstract: Thermally activated devices, including thermally activated release devices. These devices may be used as part of any device or system in which thermal activation may be desired. In particular, described herein are thermally activated devices configured as sprinkler valves. The thermally activated devices typically include a channel and a plug element, where the plug element is a shape memory material, which may be a single-crystal shape memory alloy. The channel has two connected regions, where the first region has a diameter that is greater than the diameter of a plug element in a first configuration and the second region has a diameter that is less than the diameter of the plug element in the first configuration but greater than the diameter of the plug element in its second configuration.

Abstract: Metal ingots for forming single-crystal shape-memory alloys (SMAs) may be fabricated with high reliability and control by alloying thin layers of material together. In this improved method, a reactive layer (e.g., aluminum) is provided in thin flat layers between layers of other materials (e.g., copper and layers of nickel). When the stacked layers are vacuum heated in a crucible to the melting temperature of the reactive layer, it becomes reactive and chemically bonds to the other layers, and may form eutectics that, as the temperature is further increased, melt homogeneously and congruently at temperatures below the melting temperatures of copper and nickel. Oxidation and evaporation are greatly reduced compared to other methods of alloying, and loss of material from turbulence is minimized.

Abstract: A dental archwire is provided having a pre-set shape including an elongate, curved length approximating the shape of a dental arch and a rectangular cross-section having a first dimension of 0.013-0.021 inch and a second dimension of 0.018-0.026 inch or a circular cross-section of diameter 0.013 through 0.026 inch over at least a portion of the elongate, curved length. The dental archwire in the pre-set shape comprises a hyperelastic, single crystal shape memory alloy that is free of elemental precipitates and is capable of exhibiting greater than a 10 percent strain recovery, a constant force deflection, negligible stress hysteresis, and a binding force to an orthodontic bracket equal or less than 4 N.

Abstract: Thermally activated devices, including thermally activated release devices. These devices may be used as part of any device or system in which thermal activation may be desired. In particular, described herein are thermally activated devices configured as sprinkler valves. The thermally activated devices typically include a channel and a plug element, where the plug element is a shape memory material, which may be a single-crystal shape memory alloy. The channel has two connected regions, where the first region has a diameter that is greater than the diameter of a plug element in a first configuration and the second region has a diameter that is less than the diameter of the plug element in the first configuration but greater than the diameter of the plug element in its second configuration.

Abstract: We describe herein biocompatible single crystal Cu-based shape memory alloys (SMAs). In particular, we show biocompatibility based on MEM elution cell cytotoxicity, ISO intramuscular implant, and hemo-compatibility tests producing negative cytotoxic results. This biocompatibility may be attributed to the formation of a durable oxide surface layer analogous to the titanium oxide layer that inhibits body fluid reaction to titanium nickel alloys, and/or the non-existence of crystal domain boundaries may inhibit corrosive chemical attack. Methods for controlling the formation of the protective aluminum oxide layer are also described, as are devices including such biocompatible single crystal copper-based SMAs.

Abstract: Metal ingots for forming single-crystal shape-memory alloys (SMAs) may be fabricated with high reliability and control by alloying thin layers of material together. In this improved method, a reactive layer (e.g., aluminum) is provided in thin flat layers between layers of other materials (e.g., copper and layers of nickel). When the stacked layers are vacuum heated in a crucible to the melting temperature of the reactive layer, it becomes reactive and chemically bonds to the other layers, and may form eutectics that, as the temperature is further increased, melt homogeneously and congruently at temperatures below the melting temperatures of copper and nickel. Oxidation and evaporation are greatly reduced compared to other methods of alloying, and loss of material from turbulence is minimized.

Abstract: Methods are provided for shape-setting hyperelastic, single-crystal shape memory alloy (SMA) material while preserving the hyperelastic properties of the material. A wire or rod of a single crystal shape memory alloy material is heated to an annealing temperature (Ta). While maintained at the annealing temperature, the wire or rod is shaped by driving the wire or rod and a shaping form together into contact with each other, and the shaped wire or rod is quenched in a quenching medium virtually simultaneously with the shaping.

Abstract: A method of manufacturing three-dimensional thin-film nitinol (NiTi) devices includes: depositing multiple layers of nitinol and sacrificial material on a substrate. A three-dimensional thin-film nitinol device may include a first layer of nitinol and a second layer of nitinol bonded to the first layer at an area masked and not covered by the sacrificial material during deposition of the second layer.

Abstract: Metal ingots for forming single-crystal shape-memory alloys (SMAs) may be fabricated with high reliability and control by alloying thin layers of material together. In this improved method, a reactive layer (e.g., aluminum) is provided in thin flat layers between layers of other materials (e.g., copper and layers of nickel). When the stacked layers are vacuum heated in a crucible to the melting temperature of the reactive layer, it becomes reactive and chemically bonds to the other layers, and may form eutectics that, as the temperature is further increased, melt homogeneously and congruently at temperatures below the melting temperatures of copper and nickel. Oxidation and evaporation are greatly reduced compared to other methods of alloying, and loss of material from turbulence is minimized.

Abstract: Methods are provided for shape-setting hyperelastic, single-crystal shape memory alloy (SMA) material while preserving the hyperelastic properties of the material. A wire or rod of a single crystal shape memory alloy material is heated to an annealing temperature (Ta). While maintained at the annealing temperature, the wire or rod is shaped by driving the wire or rod and a shaping form together into contact with each other, and the shaped wire or rod is quenched in a quenching medium virtually simultaneously with the shaping.

Abstract: Dental archwires of single-crystal shape memory alloys, methods of fabrication and apparatus for fabrication. A dental archwire is provided of a hyperelastic, single-crystal shape memory CuAlX alloy, where X is Ni, Mn, Nb, or Be. The dental archwire has a shape-set curved length and either a round diameter of between about 0.013 to about 0.026 inches or a rectangular cross-section with dimensions of between about 0.016 by 0.016 inches and about 0.020 by 0.030 inches.

Abstract: A temperature-activated valve for a conventional fire sprinkler utilizing a hyperelastic single-crystal shape memory alloy is described. The shape-memory element expands as it is heated, forcing a bolt to break, thereby opening the sprinkler valve. The devices described are less susceptible to accidental breakage than conventional actuators, and have fewer moving parts. Transition temperature of the shape memory alloy can be tuned to a narrow range.

Abstract: Dental arches of single-crystal shape memory alloys, methods of fabrication and apparatus for fabrication. The methods include drawing a single crystal of a shape memory alloy from a melt of the alloy. This is followed by heating, forming, and quenching the crystal sufficiently rapid to limit the formation of alloy precipitates to an amount which retains hyperelastic composition and properties of the crystal.

Abstract: We describe herein biocompatible single crystal Cu-based shape memory alloys (SMAs). In particular, we show biocompatibility based on MEM elution cell cytotoxicity, ISO intramuscular implant, and hemo-compatibility tests producing negative cytotoxic results. This biocompatibility may be attributed to the formation of a durable oxide surface layer analogous to the titanium oxide layer that inhibits body fluid reaction to titanium nickel alloys, and/or the non-existence of crystal domain boundaries may inhibit corrosive chemical attack. Methods for controlling the formation of the protective aluminum oxide layer are also described, as are devices including such biocompatible single crystal copper-based SMAs.

Abstract: Metal ingots for forming single-crystal shape-memory alloys (SMAs) may be fabricated with high reliability and control by alloying thin layers of material together. In this improved method, a reactive layer (e.g., aluminum) is provided in thin flat layers between layers of other materials (e.g., copper and layers of nickel). When the stacked layers are vacuum heated in a crucible to the melting temperature of the reactive layer, it becomes reactive and chemically bonds to the other layers, and may form eutectics that, as the temperature is further increased, melt homogeneously and congruently at temperatures below the melting temperatures of copper and nickel. Oxidation and evaporation are greatly reduced compared to other methods of alloying, and loss of material from turbulence is minimized.