Microstructure and fracture toughness of a β phase containing TiAl alloy
Microstructure and fracture toughness of a β phase containing TiAl alloy
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DOI：
10.1016/j.intermet.2011.05.006
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发表时间：
2011-10-01
期刊：
影响因子：
4.4
通讯作者：
Xiao, Shulong
中科院分区：
文献类型：
--
作者：
Chen, Yuyong;Niu, Hongzhi;Xiao, Shulong
研究了Ti-45 Al-2Nb-1.5V-1 Mo-03 Y合金的显微组织和断裂韧性。该合金具有细小的近层状显微组织，主要由细小的层状晶粒以及沿沿着层状团边界的γ相和残余β相的混合物组成。在950 ℃时效48 h后，发现从α（2）相中析出β和γ相。讨论了α（2）板条和沿着集落边界的β相变。与全层状Ti-45 Al-5 Nb-0.3Y合金相比，该合金具有较高的K（IC）值，室温下可达23.5MPam（1/2）。该合金的增韧机制为穿层断裂、韧带桥和裂纹偏转以及β和γ相的析出。细小的β和γ粒子的析出被认为是本征增韧机制，因为析出产生的α（2）/β和α（2）/γ界面能有效地限制位错运动。皇冠版权所有（C）2011由爱思唯尔有限公司出版。保留所有权利。
Microstructures and fracture toughness of Ti-45Al-2Nb-1.5V-1Mo-03Y alloy have been investigated. The alloy exhibits fine nearly lamellar microstructures, consisting mainly of fine lamellar grains, together with mixtures of gamma and residual beta phases along lamellar colony boundaries. Precipitation of both beta and gamma phases from alpha(2) lamellae was found after aging at 950 degrees C for 48 h. Phase transformations involving beta Phase both in alpha(2) laths and along colony boundaries are discussed. This TiAl alloy possesses a higher K(IC) value up to 23.5 MPam(1/2) at room temperature, compared with fully lamellar Ti-45Al-5Nb-0.3Y alloy. The toughening mechanism for current alloy is concluded as trans-lamellar fracture, ligament bridges and crack deflection, together with precipitation of beta and gamma phases. The precipitation of fine beta and gamma particles is considered as intrinsic toughening mechanism, because alpha(2)/beta and alpha(2)/gamma interfaces generating due to precipitation can restrict dislocation motion effectively. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.