CREEP CAVITATION IN ALUMINUM CONTAINING HIGH VOLUME FRACTIONS OF SUBMICRON ALUMINA PARTICLES

摘要

Density measurements were used to quantify creep cavitation in pure aluminum containing high volume fractions (25-42 vol. percent) of alumina particles with a mean diameter of 280 run. In the range of creep temperatures studied (370-450 deg C), the cavity fraction increases linearly with strain, i.e. the ratio of cavity fraction to strain is constant. This cavitation ratio (i) decreases with increasing stress at constant temperature; (ii) is very weakly dependent on temperature at constant stress; (iii) increases with increasing volume fraction of dispersoids at constant stress and temperature; (iv) is independent of matrix grain size. The latter result indicates that cavitation occurs at particle /matrix interfaces, not at matrix grain boundaries.