An examination of creep data for an Al-Mg composite
- Univ. of Southern California, Los Angeles, CA (United States)
In a recent investigation of the creep behavior of an Al-4 wt pct Mg composite reinforced with 10 vol pct of SiC particles, henceforth designated Al-4 pct Mg-10 vol pct SiC(p), Pandey et al. obtained a plot of the steady-state creep rate, {dot {epsilon}}, vs the applied stress, {sigma}, over the temperature range from 573 to 673 K. The present analysis leads to two conclusions. First, the experimental data reported by Pandey et al. for an Al-4 pct Mg-10 vol pct SiC(p) composite divides into two distinct creep regimes at all testing temperatures, with a transition with increasing stress from region I to region II at a strain rate of {approximately}3 {times} 10{sup {minus}8} s{sup {minus}1}. Second, a detailed examination of the data at the higher stresses in region II does not support a constant structure model for creep, as proposed by Pandey et al., but rather it leads to a true stress exponent ({approximately}3.0) and a true activation energy for creep ({approximately}125 kJ mol{sup {minus}1}) which are consistent with control by the viscous glide of dislocations dragging Mg solute atom atmospheres within the Al-Mg matrix.
- Sponsoring Organization:
- Department of the Army, Washington, DC (United States)
- OSTI ID:
- 509185
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 5 Vol. 28; ISSN 1073-5623; ISSN MMTAEB
- Country of Publication:
- United States
- Language:
- English
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