The creep properties and microstructures of gamma-tial reinforced with continuous al2o3 fibers have been investigated. novel fiber coating concepts have been used to create "weak" fiber/matrix interfaces that allow the fibers to impart enhanced creep and fracture resistance, simultaneously. several major facets of the creep behavior were identified. under conditions of limited fiber fracture, creep-resistant sapphire fibers were found to limit longitudinal creep to a short transient strain, consistent with ...
Refractory compounds grown from the melt offer significant potential for high temperature reinforcement of titanium aluminides. in principle, the strengthening arises from the constrained plastic flow of the matrix around the refractory second phases, which must be thermodynamically stable, have high aspect ratios and be of a scale larger than the dislocation cell size. the reinforcing phase morphology and size scale may be tailored by suitable control of the alloy ...
Additions of ^5%b and ^9%ta to binary gamma-tial result in the formation of a monoboride isomorphous with tib but containing ta in solid solution. this boride exhibits strongly anisotropic growth from the melt, producing rod-like primary phases which are of potential interest for creep strengthening of the gamma matrix. fibrous borides with aspect ratios larger than ^20 and volume fractions of ^0.12 have been produced in arc-melted ti-48al-9ta-4.3b alloys. creep ...
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