Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5455817 | Materials Science and Engineering: A | 2017 | 8 Pages |
Abstract
The dynamic compressive mechanical properties of the alloy Mg-4Zn-3Gd-1Ca (wt%) and its nanocomposite Mg4Zn3Gd1Ca-2ZnO were investigated at strain rates up to 1Ã103 sâ1, using a Split Hopkinson Pressure Bar (SHPB) tester. Under dynamic loading, the addition of 2 wt% ZnO nanoparticles into the alloy generated a significant strength increase (~100 MPa), attributed largely to grain refinement. Negative strain rate sensitivity of the alloy and its nanocomposite was observed. It is postulated that the strengthening influence of the nanoparticles by retarding twin nucleation/growth at grain boundaries, is significantly weakened as strain rate increases. The yield stress of the materials studied follows the Hall-Petch relationship even when the grain size is less than 1 µm. It is proposed that the strong solute strengthening from Gd and Ca enhances the critical resolved shear stress for slip and preserves tension twinning as the dominant deformation mechanism for yielding.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Y. Chen, S. Tekumalla, Y.B. Guo, R. Shabadi, V.P.W. Shim, M. Gupta,