Maintaining High Strength at High Temperature in a Mg-Y-Zn-Gd Alloy by Heat Treatments and Severe Deformation Processing

The evolution of mechanical properties between room temperature and 573 K (300 °C) has been studied in a Mg-Y-Zn-Gd alloy under different heat treated and thermomechanically processed conditions. The different distributions of longperiodstackingordered phase and precipitation of lamellar Gd-rich phase, modified by severe deformation processing, lead to strengths ranging between 112 and 175 MPa at 573 K (300 °C). Microstructures have been evaluated under different processing conditions and comparison made with a similar alloy without Gd previously studied. Although the alloys can achieve similar room temperature strengths, only the Gd-containing alloy can retain sufficient high strength at temperatures above 473 K (200 °C). This is due to the strengthening effect of the lamellar Gd-rich precipitates that are broken and redistributed during the severe deformation processing.We would like to acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness under project number MAT2012-34135.Peer Reviewe