A new processing technique, called in this study as high-pressure sliding (HPS), was developed as a process of severe plastic deformation (SPD). The HPS facility consists of two anvils and one plunger and each of two sheet samples is placed between the upper anvil and the plunger and the lower anvil and the plunger. As illustrated in Fig.1, the plunger is pushed with respect to the anvils to introduce shear strain in the sheet samples. The samples after HPS are shown in Fig.2 for pure Al (99.99%). Application of HPS led to significant grain refinement with the same hardness level as reported using conventional high-pressure torsion (HPT) as shown in Fig.3. Transmission electron micrographs are shown in Fig.4. It is found that the grain size and microstructural features are similar to those produced by HPT. It is demonstrated that HPS can be used as an SPD process for microstructural refinement and subsequent enhancement of tensile strength ductility as shown in Fig.5.
Development of High-Pressure Sliding for Microstructural Refinement of Rectangular Metallic Sheets
[Published in Materials Transactions, 50, (2009), pp. 930-933.]
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Fig. 1 Schematic illustration of HPS. (a) assembly of two anvils with guiding pins, one plunger and two thin sheet samples. (b) cross sectional view of assembly. |
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Fig. 2 Appearance of sheet sample (a) before HPS, and after HPS (b) for view from upper anvil (UA surface), (c) for side view and (d) for view from upper side of plunger (UP surface). |
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Fig. 3 Vickers micohardness obtained by HPS for sliding distances of 5, 10, 15 and 30 mm. They are plotted against equivalent strain on graph obtained earlier. |
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Fig.4 Bright field images (upper) and dark field images (lower) including SAED patterns. |
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Fig.5 Nominal stress versus nominal strain for samples processed by HPS for sliding distances of 5, 10, 15 and 30 mm. |