No abstract

No abstract

Near-␥ TiAl-and Al 3 Ti-based intermetallic matrix composites have been produced using in-situ reaction-synthesis techniques. The intermetallic matrices have been reinforced with relatively high loadings (e.g., 20 to 50 vol pct) of dispersed TiB 2 particulates. It is shown that the as-synthesized TiB 2 size is strongly dependent on the specific alloy formulation; specifically, the TiB 2 size tends to increase as the nominal volume percent of TiB 2 in the composite increases. The observed size effect is determined to be associated with the temperature that is attained during the synthesis event, which is established primarily by the net exothermicity of the participating synthesis reaction(s). The exothermicity of the reactions can be assessed through the calculation of a formulation's adiabatic temperature, which is found to increase with the percentage of TiB 2 over the range of approximately 10 to 60 vol pct. The coupling of a composite's characteristic adiabatic temperature with the resulting reinforcement size provides direct links among composition, processing, and mechanical performance, since the size of a reinforcing particle is influential in establishing the interparticle spacing, which, in turn, establishes the strengthening potency of the dispersed phase within the composite.

An test coil was manufactured and tested as the first step in the development of a 3 T magnet system. Due to the fact that has a higher critical temperature, replacing conventional NbTi superconductor with , higher temperature operation will be possible. It will make the cryogenic design much simpler and less expensive.Furthermore, operating the magnet at higher temperature results in larger heat capacity of the materials and surrounding structures. Higher heat capacity, therefore, results in increased thermal stability of the magnet against quench initiation.The 3 T magnet design consists of several coils. One of the center coils was manufactured for testing the performance at higher temperatures. The test coil was conduction cooled and the quench performance of the coil was good, which means there were no critical issues during the coil manufacturing process. However, AC loss heating, as well as a small resistance of the coil was found, both of which might result from wire design, manufacture, and quality.

No abstract