Microstructure and room temperature mechanical properties of hypereutectic Nb-Si based alloy processed by directional solidification

作者：Yuan S N; Jia L N; Ma L M; Jiang H; Zhang H^*

来源：Materials Science and Technology, 2014, 30(1): 75-80.

DOI：10.1179/1743284713Y.0000000303

• Nb-Si based alloy
• Directional solidification
• Heat treatment
• Microstructure
• Tensile strength
• Fracture toughness

In this investigation, Nb-16Si-24Ti-4Cr-2Al-2Hf alloy was directionally solidified and then heat treated, and the microstructure, fracture toughness K-Q and tensile strength sigma(b) of the alloy were studied. The directionally solidified microstructure consisted of primary Nb5Si3 blocks and Nb-SS+Nb5Si3 eutectic cells. The cross section of eutectic cells changed from the square morphology to the nearly round morphology with the increasing withdrawal rate. During heat treatment, the boundaries of the round eutectic cells were eliminated as the Nb-SS connected to be a net-like structure. The values of K-Q and sigma(b) increased with the increase of withdrawal rate. The toughening from the crack deflection of continuous Nb-ss network was significant and refinement of the microstructure improved the tensile strength in heat treated samples.

• 出版日期2014-1
• 单位北京航空航天大学