Achieving high strength/ductility in bulk W-Zr-Y2O3 alloy plate with hybrid microstructure

• Bulk W-0.2wt%Zr-1.0wt%Y2O3 (WZY) and W-1.0wt%Y2O3 (WY) alloy plates were fabricated by hot pressing sintering and hot rolling.
• The ductile-brittle transition temperature of the rolled WZY is ~ 150 °C and the ultimate tensile strength values are larger than 580 MPa.
• Both the tensile strength and elongation of the rolled WZY are higher than that of the rolled WY.
• WZY alloys with hybrid structures of refined sub-grains, elongated mother grains and dispersed nanoparticles are obtained by Zr addition and hot rolling.

A hybrid microstructure design strategy which achieves 6.5 mm thick W-0.2 wt% Zr-1.0 wt% Y2O3 (WZY) alloy plates with a DBTT lower than 150 °C is reported. The WZY alloy is brittle at 100 °C with an ultimate tensile strength (UTS) of 798 MPa and shows detectable plastic deformation at 150 °C with a total elongation (TE) ~ 3.2% and a UTS of 911 MPa. The UTS of this WZY alloy is larger than 580 MPa from RT to 500 °C and the TE increases to ~ 23.2% at 400 °C. The processing route combining micro-alloying, hot rolling and nano-sized oxide dispersion strengthening leads to a hybrid microstructure with refined equiaxed sub-grains, elongated mother grains and dispersed nanoparticles, which significantly strengthens/toughens the W alloys.

(Left panel) a concise schematic diagram summarizing the major uniqueness involved in the designed bulk WZY alloy. (Middle panel) the ultimate tensile strength of rolled WZY and WY alloys at different temperatures. (Right panel) the total elongation of rolled WZY and WY alloys at different temperatures.Figure optionsDownload as PowerPoint slide