STATISTICAL PROPERTIES OF THE TENSILE-STRENGTH OF B AL COMPOSITES AT ELEVATED-TEMPERATURES/

Tensile tests of a 10 vol% boron-aluminum composite were carried out a t room temperature, 150 degrees C and 300 degrees C, in order to inves tigate the validity of the finite-element simulation proposed in the p revious report which can evaluate the tensile strength of fiber-reinfo rced metals. The simulated average strengths were in good agreement wi th the experimental results, though the scatter of strength was somewh at underestimated. The fiber stress distributions around a broken fibe r were analyzed by FEM, by taking into account the matrix constitutive equation at each temperature, From the results of analysis and the st ochastic model based on a Markov chain theory, the relation between th e fiber stress distributions and the statistical properties of composi te strength obtained in the experiment and the simulation was discusse d. It was pointed out that, consequently, the statistical properties o f room temperature strength would be maintained to some degree at elev ated temperatures, unless the fibers were degraded severely. Additiona lly, the effect of thermal stresses occurring in the composite on the tensile strength was investigated.