Patents by Inventor Haavard Gjestland

Haavard Gjestland has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5501748
    Abstract: Procedure for the production of a thixotropic magnesium alloy by adding a grain refiner combined with controlled, rapid solidification with subsequent heating to the two-phase area. It is preferable to use a solidification rate of >1.degree. C./s, more preferably >10.degree. C./s. It is essential that the solidification takes place at such a speed that growth of dendrites is avoided. Heating to the two-phase area is carried out rapidly in 1-30 minutes, preferably 2-5 minutes. By heating an alloy comprising 2-8 weight % Zn, 1.5-5 weight % RE, 0.2-0.8 weight Zr balanced with magnesium to a temperature in the two-phase area after casting, the structure will assume a form in which the .alpha.-phase is globular (RE=rare earth metal). The size of the spheres will be dependent on the temperature and the holding time at that temperature and they will be surrounded by a low-smelting matrix. It is preferable that the alloy has a grain size of not greater than <100 .mu.m, more preferably 50-100 .mu.m.
    Type: Grant
    Filed: June 10, 1993
    Date of Patent: March 26, 1996
    Assignee: Norsk Hydro A.S.
    Inventors: Haavard Gjestland, HAkon Westengen