University of Michigan

Jyotirmoy Mazumder

Lijun Song

Cunshan Wang

Ashish K Dasgupta

Jeongyong Choi

A method and apparatus for direct writing of single crystal super alloys and metals. The method including heating a substrate to a predetermined temperature below its melting point; using a laser to form a melt pool on a surface of the substrate, wherein the substrate is positioned on a base plate, and wherein the laser and the base plate are movable relative to each other, the laser being used for direct metal deposition; introducing a superalloy powder to the melt pool; and controlling the temperature of the melt pool to maintain a predetermined thermal gradient on a solid and liquid interface of the melt pool so as to form a single crystal deposit on the substrate. The apparatus configured to generally achieve the aforementioned method.

Apparatus and method for direct writing of single crystal super alloys and metals

A microstructure detector and in-situ method for real-time determination of the microstructure of a material undergoing alloying or other phase transformation. The method carried out by the detector includes the steps of: (a) detecting light emitted from a plasma plume created during phase transformation of a material; (b) determining at least some of the spectral content of the detected light; and (c) determining an expected microstructure of the transformed material from the determined spectral content. Closed loop control of the phase transformation process can be carried out using feedback from the detector to achieve a desired microstructure.

In-situ identification and control of microstructures produced by phase transformation of a material

An ultra-short pulse laser physically and/or chemically modifies a substrate surface. A laser ablation process is configured to form raised surface features on the substrate. The laser also functions as the energy source in a chemical vapor deposition (CVD) process. The laser delivers energy to the substrate with parameters such as pulse energy, size, duration, and spacing sufficient to simultaneously vaporize substrate material and cause the substrate material to react with a controlled environment that includes constituents of a desired coating composition. A battery electrode having a face with microneedle features coated with an active metal compound can be produced by the process. The active metal compound is a lithium-containing compound in a lithium-ion battery.

Pulsed laser chemical vapor deposition and surface modification

A method for laser welding a pair of overlapping metal members together and a weld joint produced by the method. At least one of the metal members has a protective metal coating. The method includes applying a thin layer of an alloying agent on at least one of the metal members between the metal members, melting the protective metal coating and the alloying agent to form an alloy that is disposed between the overlapping members with zero gap, welding the overlapping metal members together to form a weld, and controlling the amount of the alloying agent such that the extended solid solubility of the alloying agent in the weld is not exceeded.

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Ann Arbor, MI, United States of America

Jyotirmoy Mazumder