Abstract
Longitudinal creep tests of a 6-ply unidirectional SCS-6/Beta21S metal matrix composite with 38 percent fiber volume fraction were performed at three temperatures of 450, 500 and 550°C at four stresses ranging from 900 to 1350MPa. Elongation and acoustic emission in the gage section were measured during creep testing, and the specimens were subjected to observation of the fibers exposed by etching the outer matrix layers after creep testing. Also performed were creep tests of the matrix material and tensile tests of the fibers extracted from a virgin specimen. In the creep tests of the composite it was observed that the increase of temperature hastened greatly creep rupture while fiber damage and acoustic emission occurred with little dependence on temperature. It was shown that the activation of matrix creep with temperature is mainly responsible for hastening creep rupture of the composite. Besides it was shown that the fiber bundle strength determined from the tensile tests of extracted fibers is effective in estimating the level of applied stress at which the composite survived long in the creep tests.
