The influence of Sc addition on the high temperature compressive strength of a commercial
alloy 7010 (hereafter termed base alloy) has been examined. The base alloy, and the base alloy with 0.23
wt% Sc were cast, homogenized and subjected to compression tests at temperatures ranging from 300 to
450oC and strain rates of 10-3, 10-2, 10-1 and 1 sec-1. It is shown that Sc addition to the base alloy increases
the compressive flow stress under these deformation conditions. The increase in peak flow stress is nearly
3-6 times the peak flow stress of the base alloy at temperatures 300-350oC over the strain rate range
investigated. Whilst, at temperatures ³ 400oC, the flow stresses decrease significantly irrespective of the
strain rate used. Transmission electron microscopy (TEM) revealed that a combination of (1) increased
nucleation frequency of dispersoids, (2) evolution of smaller subgrain size, and (3) refinement of alloy
phases in the Al-Zn-Mg-Cu system contribute to superior strengthening in the alloy containing Sc. Whilst,
it is primarily a combination of coarsening and instability of the alloy phases in the Al-Zn-Mg-Cu system
that dramatically reduces the flow stresses in both the alloys at temperatures ³ 400oC.
Research on testing method of resin sand high temperature compressive strength
