THE EFFECT OF CUAl2 DISPERSIONS ON THE FATIGUE OF ALUMINUM-COPPER ALLOYS
CALIFORNIA UNIV BERKELEY MATERIALS RESEARCH LAB
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The fatigue properties of Al-Cu alloys containing CuAl sub 2 dispersions were measured at room temperature. The properties were substantially independent of the degree of dispersion the coarser dispersions had slightly higher fatigue strengths. The same dispersions in spheroidal steels exhibit 50 increases in flow stress and endurance limit. A study of the nature of crack formation in the alloys revealed that the nucleation of micro-cracks depended primarily on the critical resolved shear stress on slip planes. Final failure was attributed to the accumulation and coalescence of micro-cracks in the grain- boundary regions. The fatigue properties of the alloys may be improved by the introduction of preferred orientations in which the 111 poles fall outside the regions susceptible to rapid crack nucleation.
- Properties of Metals and Alloys