Structural parameters of strength of two-phase alloys with plastic matrix

Dislocation structure and failure morphology for the two-phase Al-Be-Mg alloys mith plastic Al-matrix and volume content of Be-particles to 32.7% are studied by light transmission and electron scanning microscopy methods. In the frames of notions based on application of statistical methods of the experiment theory a structural sensitivity of strength characteristics is discussed and correctness of the Hall-Petch and Mott-Stro dislocation (barrier) models is first proved for two-phase alloys with plastic matrix. It is shown that the yield point (σyield) of the alloy at the temperatures of 20-400 deg C obeys the Hall-Petch criterion (σyield(dAlcell)-1/2) for the cell structure formed under substructural strengthening of the Al-matrix, while the breaking stress (σb) - the Mott-Stro criterion σb(dBe)-1/2 for quasibrittle Be-particles of maximal size dBe. A critical stage of failure and the Griffits-Orovan local criterion are established for the unstable crack propagation in two-phase alloys with a plastic matrix