The Influence of Growth Rate and Temperature on High Cycle Fatigue of Al-Al(3)Ni.
RENSSELAER POLYTECHNIC INST TROY N Y DEPT OF MATERIALS ENGINEERING
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High-cycle fatigue tests have been conducted on specimens of an Al-Al3Ni eutectic alloy, unidirectionally solidified at selected rates from 0.5cmhr to 1200cmhr. Tests were conducted in air at 298K98K, 458K and 683K. Room temperature fatigue lives were independent of growth rate at low solidification rates but were markedly improved in samples grown at 1200cmhr. The dependence of fatigue life on growth rate at elevated temperatures appears to be due primarily to differences in cyclic creep rates as a result of varying interfiber spacings. Crack initiation and propagation mechanisms were established by metallographic and fractographic examination. Dislocation substructure-fiber interactions were studied by transmission electron microscopy.
- Properties of Metals and Alloys