Grumman Aerospace Corporation

David J Larson, Sr

Ronald Gary Pirich

John Frederick Klein

James R Kennedy

Victor Curreri

Janine E Dubois

Fatigue lifetime enhancement of the holes formed in structural members occurs by introducing a cold working tool or interference fit fasteners fabricated from shape memory alloy materials. The tool may be employed to expand the wall of a hole while the tool material is raised above the critical transitional temperature. Then, upon lowering the tool material below the critical transitional material, it contracts permitting it to be withdrawn. Bushings and interference fit fasteners may be installed in holes formed in structural members when a shape alloy material bushing or fastener is heated above the critical transitional temperature so that an interference fit results and the hole is cold worked. If the alloy material is not cooled below the critical transitional temperature, the interference fit may be permanently maintained, thereby further enhancing the fatigue life of the members.

Method of cold working holes using a shape memory alloy tool

A heating system has a substantially cylindrical hollow muffle formed of a alumina ceramic with a plurality of heat-generating windings therearound. A light-actuated power control is operatively connected to the windings. A computer is operatively connected to a temperature monitor associated with an article being heated in the muffle. The computer is also operatively connected to a light-signal generator and provides commands to the generator in the form of a train of equidistantly spaced electrical pulses in response to temperature measurements provided by the monitor such that an article can be heated to an elevated steady state temperature and controlled at that steady state temperature within precise predetermined limits. The precise temperature control makes the system particularly valuable in the fabrication of crystals with uniform properties or having special growth requirements.

Computerized multi-zone crystal growth furnace

Directional solidification of Bi and Mn compositions to produce magnetic single domain size MnBi particles with aligned morphologies followed by post heat treating and densification.

Directional solidification and densification of permanent magnets having

Directional solidification of Bi and Mn compositions to produce magnetic single domain size MnBi particles with aligned morphologies.

A substrate coating of a ferromagnetic alloy of a rare earth-transition element mixture is prepared by a hollow cathode sputtering deposition method to produce near single domain films on various substrates.

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Huntington Station, NY, United States of America

David J Larson, Sr