Role of melt percentage on characteristics of Al-Zn-Mg/3 wt.% Al2O3 nanostructured composite modified through semi-solid thermomechanical processing
Abstract
A thermomechanical processing (TMP) method was employed to modify the characteristics of Al-Zn-Mg/3 wt% Al2O3 composite including the microstructure and the mechanical properties. The composite powders were subsequently cold pressed at 115 MPa and solid state sintered at 550 °C for 90 min under argon atmosphere. The TMP was then performed on the samples consisting of an additional cold pressing at 250 MPa followed by a partial remelting stage in the semi-solid state for 30 min under argon atmosphere. Four different temperatures corresponding to four percentages of melt content were chosen to apply in the TMP to study the role of the melt content on the microstructure and mechanical properties of the modified samples. The observations obtained from the characterizations and mechanical tests showed that drastic alteration in the solid sintered microstructure occurred by reducing the porosity level and creating a solidified network as grain boundaries. However, with increasing the melt percentage up to 20%, decreasing the average grain diameter along with increasing the microhardness and compressive strength was observed.
- Publication:
-
Materials Research Express
- Pub Date:
- February 2018
- DOI:
- 10.1088/2053-1591/aaabf8
- Bibcode:
- 2018MRE.....5b6520H