Abstract: Core-shell microparticles, along with methods of their fabrication and use, are provided. The core-shell microparticles may include a core comprising a first metallic material having a first chromium content and a shell surrounding the core and comprising a second metallic material having a second chromium content that is less than the first chromium content. For example, the first chromium content may be 5% by weight or greater of elemental chromium within the first metallic material.

Abstract: A directed energy deposition system and method including a set of nozzles for directing material, such in the form of a particle stream, at a part and a set of energy sources for generating a melt pool as the material contacts the part. The system further includes apparatus for generating a sound field that controls characteristics of the particle stream as it passes through the sound field.

Abstract: A method for printing a strain sensor on a component using an aerosol ink, the method including depositing the aerosol ink on the component using a print head, the aerosol ink comprising chromium containing particles, and monitoring a printing environment parameter associated with printing environment conditions to confirm the printing environment parameter is within a predetermined environmental range of a printing environment parameter baseline value while depositing the aerosol ink on the component using the print head, the printing environment parameter baseline value a predetermined preferred printing environment parameter value within the predetermined environmental range, the monitoring including monitoring an atmospheric composition of the printing environment.

Abstract: Methods for making a plurality of microparticles from a reaction solution that includes an organic acid in a solvent are provided. An example aerosol ink includes a plurality of palladium-chromium metallic microparticles dispersed in a solvent system, wherein the plurality of palladium-chromium metallic microparticles include a palladium-chromium alloy.

Abstract: A method is provided for determining optimal values of significant process parameters in an additive manufacturing (AM) process for printing a part from a specified process material. The method involves defining a set of target output material properties to be optimized and identifying an initial set of process parameters pertaining to the AM process. The method broadly comprises a screening phase and an optimization phase. The screening phase involves generating and executing a first experiment design, and determining, based on a first output response, a subset of significant process parameters that affect the target output material properties. The optimization phase involves generating and executing a second experiment design, and determining, based on a second output response, optimal values for the significant process parameters that maximize or minimize the target output material properties.

Abstract: Methods for making a plurality of microparticles from a reaction solution that includes an organic acid in a solvent are provided. The method may include adding a chromium salt and a palladium salt to the reaction solution; bringing the reaction solution to a reaction temperature of 0° C. to 150° C. to form palladium cations and chromium cations within the reaction solution such that the palladium cations and chromium cations combine to form the plurality of microparticles that precipitate from the reaction solution; and collecting the microparticles from the reaction mixture. The plurality of microparticles comprises a palladium-chromium alloy. The palladium-chromium alloy may comprise chromium in a weight percentage of 1% to 20% of the total weight of the palladium-chromium alloy.

Abstract: A method for printing a strain sensor on a component using an aerosol ink, the method including depositing the aerosol ink on the component using a print head, the aerosol ink comprising chromium containing particles, and monitoring a printing environment parameter associated with printing environment conditions to confirm the printing environment parameter is within a predetermined environmental range of a printing environment parameter baseline value while depositing the aerosol ink on the component using the print head, the printing environment parameter baseline value a predetermined preferred printing environment parameter value within the predetermined environmental range, the monitoring including monitoring an atmospheric composition of the printing environment.

Abstract: A method for printing a strain sensor on a component using an aerosol ink includes depositing the aerosol ink on the component using a print head, the aerosol ink including chromium containing alloy particles; and monitoring a printing environment parameter to confirm the printing environment parameter is within a predetermined environmental range of a printing environment parameter baseline value while depositing the aerosol ink on the component using the print head.

Abstract: A method for printing a strain sensor on a component using an aerosol ink includes depositing the aerosol ink on the component using a print head, the aerosol ink including chromium containing alloy particles; and monitoring a printing environment parameter to confirm the printing environment parameter is within a predetermined environmental range of a printing environment parameter baseline value while depositing the aerosol ink on the component using the print head.

Abstract: Methods for making a plurality of microparticles from a reaction solution that includes an organic acid in a solvent are provided. The method may include adding a chromium salt and a palladium salt to the reaction solution; bringing the reaction solution to a reaction temperature of 0° C. to 150° C. to form palladium cations and chromium cations within the reaction solution such that the palladium cations and chromium cations combine to form the plurality of microparticles that precipitate from the reaction solution; and collecting the microparticles from the reaction mixture. The plurality of microparticles comprises a palladium-chromium alloy. The palladium-chromium alloy may comprise chromium in a weight percentage of 1% to 20% of the total weight of the palladium-chromium alloy.

Abstract: An aerosol ink is generally provided, along with methods of forming an aerosol ink. In one embodiment, the aerosol ink includes a plurality of chromium-containing metallic microparticles dispersed in a solvent system. Generally, the chromium-containing metallic microparticles comprise elemental chromium mixed with at least one alloying element. A non-contact method is also generally provided of forming a chromium-containing metallic layer on a surface of a substrate.

Abstract: Core-shell microparticles, along with methods of their fabrication and use, are provided. The core-shell microparticles may include a core comprising a first metallic material having a first chromium content and a shell surrounding the core and comprising a second metallic material having a second chromium content that is less than the first chromium content. For example, the first chromium content may be 5% by weight or greater of elemental chromium within the first metallic material.

Abstract: The disclosure is directed at a method and system for three-dimensional (3D) printing of flexible graphene electronic devices and deposition of graphene on non-planar surfaces. By using a printer ink that includes a stabilized graphene powder and a pair of solvents, the printer ink provides for a material that overcomes disadvantages of current systems. In one embodiment, the pair of solvents are cyclohexanone and terpineol. The stabilized graphene powder preferably includes a polymer such as, but not limited to ethyl cellulose.

Abstract: A system and method for additive manufacturing of heterogeneous porous structures, and structures made therefrom. The system includes: a powder feeding module for depositing layers of powder material; a binder module for dispensing powder binding material; a porogen module for selectively depositing at least one porogen to the layers of powder material, wherein the at least one porogen is removable to produce at least one predetermined porosity in the part; and a controller to control the powder feeding module, binder module and porogen module. The method includes: forming a layer by performing at least one of: applying a powder to a substrate; applying a binder to the powder; applying at least one porogen to the powder based on a predetermined pattern; and forming additional layers until a predetermined number of layers is reached, wherein at least one of the layers includes a porogen.

Abstract: The disclosure is directed at a method and system for three-dimensional (3D) printing of flexible graphene electronic devices and deposition of graphene on non-planar surfaces. By using a printer ink that includes a stabilized graphene powder and a pair of solvents, the printer ink provides for a material that overcomes disadvantages of current systems. In one embodiment, the pair of solvents are cyclohexanone and terpineol. The stabilized graphene powder preferably includes a polymer such as, but not limited to ethyl cellulose.

Abstract: A dual-parameter optical sensor having: a fiber optic cable; a fiber Bragg grating (FBG) section provided on the fiber optic cable; and a sleeve affixed to the fiber optic cable such that the sleeve encloses a predetermined portion of the FBG section, wherein the sleeve has a different thermal expansion co-efficient than the fiber optic cable. A method for manufacturing the dual-parameter optical sensor including selecting a fiber optic cable having a predetermined thermal expansion coefficient; forming a fiber Bragg grating (FBG) section on the fiber optic cable; selecting a sleeve having a predetermined thermal expansion co-efficient that is different from the thermal expansion co-efficient of the fiber optical cable; selecting a predetermined portion of the FBG section to be enclosed by the sleeve; and joining the fiber optic cable to the sleeve such that the sleeve encloses the selected predetermined portion of the FBG section.

Abstract: A superstructure fiber Bragg gratings (FBG) by laser-assisted direct writing of on-fiber metallic films. A laser direct write method is used to fabricate periodic films of silver nanoparticles on the non-planar surface of as-fabricated FBGs. Silver films with a thickness of about 9 ?m are fabricated around a Bragg grating optical fiber. The performance of the superstructure FBG is studied by applying temperature and tensile stress on the fiber. An opto-mechanical model is also developed to predict the optical response of the synthesized superstructure FBG under thermal and structural loadings. The reflectivity of sidebands in the reflection spectrum can be tuned up to 20% and 37% under thermal and structural loadings, respectively. In addition, the developed superstructure FBG is used for simultaneous measurement of multiple criteria such as force and temperature to eliminate the inherent limitation of regular FBGs in multi-parameter sensing.

Abstract: A system and method for additive manufacturing of heterogeneous porous structures, and structures made therefrom. The system includes: a powder feeding module for depositing layers of powder material; a binder module for dispensing powder binding material; a porogen module for selectively depositing at least one porogen to the layers of powder material, wherein the at least one porogen is removable to produce at least one predetermined porosity in the part; and a controller to control the powder feeding module, binder module and porogen module. The method includes: forming a layer by performing at least one of: applying a powder to a substrate; applying a binder to the powder; applying at least one porogen to the powder based on a predetermined pattern; and forming additional layers until a predetermined number of layers is reached, wherein at least one of the layers includes a porogen.

Abstract: A superstructure fiber Bragg gratings (FBG) by laser-assisted direct writing of on-fiber metallic films. A laser direct write method is used to fabricate periodic films of silver nanoparticles on the non-planar surface of as-fabricated FBGs. Silver films with a thickness of about 9 ?m are fabricated around a Bragg grating optical fiber. The performance of the superstructure FBG is studied by applying temperature and tensile stress on the fiber. An opto-mechanical model is also developed to predict the optical response of the synthesized superstructure FBG under thermal and structural loadings. The reflectivity of sidebands in the reflection spectrum can be tuned up to 20% and 37% under thermal and structural loadings, respectively. In addition, the developed superstructure FBG is used for simultaneous measurement of multiple criteria such as force and temperature to eliminate the inherent limitation of regular FBGs in multi-parameter sensing.

Abstract: A system is disclosed for monitoring and controlling laser cladding process by powder injection in real-time. The invention combines laser cladding technique along with automated direct feedback control to achieve a good quality clad in terms of dimensional and metallurgical characteristics. The system uses optical CCD-based detectors as the feedback system. The optical CCD-based detectors along with a pattern recognition algorithm is used to determine the clad characteristics in real-time. These characteristics are clad's dimensions, solidification rate, and roughness that are fed into a closed loop control system to adjust the laser power and table velocity to produce desired clad quality.