| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1298337 | Solid State Ionics | 2011 | 4 Pages |
The positron annihilation lifetime spectroscopy (PALS) study and load dependent Vickers microhardness data were applied together to find correlation between free-volume defects and microstructure in the pure As2S3 and metal-modified (As2S3)85Ag15 and (As2S3)85(AgI)15 glasses. The PALS data were analyzed by the well-developed formalism of the two-state positron trapping model while microhardness data were analyzed according to the strain-gradient plasticity theory presented in the form: H = H0(1 + d0/d), where H0 is the load independent hardness and d0 is a constant. Analysis of the experimental results showed that: (1) the hole-like defects with volume larger than or comparable with the size of the Ag+ ions but smaller than the size of the AgI clusters are present in the structure of the host glass matrix As2S3 and are effective positron traps, and (2) these free-volume defects determine the load-independent indentation microhardness H0 of a glass in the region of applied load where the HV decreases with an increase in the applied load P.
Research Highlights► The hole-like defects are present in the structure of the host glass matrix As2S3. ► These free-volume defects are effective positron traps. ► The volume of these defects is found to be about size of the Ag+ ions (18-20 Å3). ► These free-volume defects determine the load-independent indentation microhardness.
