Mg based bulk metallic glasses: Glass transition temperature and elastic properties versus toughness

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	Mg based bulk metallic glasses: Glass transition temperature and elastic properties versus toughness
	L. L. Shi ; J. Xu
刊名	Journal of Non-Crystalline Solids
	2011
卷号	357 期号:15 页码:2926-2933
关键词	Metallic glasses Glass transition Toughness Elastic constant Structural relaxation structural relaxation forming ability amorphous-alloys ternary-system critical size high-strength fracture embrittlement plasticity gd
ISSN号	0022-3093
中文摘要	In this work, optimal compositions for bulk metallicglasses (BMGs) formation in the ternary Mg-Cu-Nd and Mg-Ni-Nd systems are located at the Mg(57)Cu(34)Nd(9) and Mg(64)Ni(21)Nd(15), respectively, with the critical diameter of 4 mm for the rods fabricated by copper mold casting. As indicated by notch toughness testing, Mg(64)Ni(21)Nd(15) BMG (K(Q) = 5.1 MPa root m) manifests higher toughness with respect to the Mg(57)Cu(34)Nd(9) (K(Q) = 3.6 MPa root m), even though both BMGs have similar compressive fracture strength of 870-880 MPa. Such an improvement in toughness for Mg BMGs correlates with the reduction of shear modulus and the enhancement of thermal stability to resist to the structural relaxation at room temperature, which is indicated by the elevated glass transition temperature T(g). Under the Model loading condition, morphology in fracture surface of the Mg(64)Ni(21)Nd(15) BMG varies along the crack propagation path. Fractographic evolution of the fracture surface follows the Taylor's meniscus instability criterion. For the Mg-based BMGs, shear modulus scales with the glass transition temperature, and can be expressed as mu = 4.7 + 625T(g)/V(m)[1-4/9(T/Tg)(2/3)]. Meanwhile, correlation between the calorimetric T(g) and elastic properties at T(g) can be rationalized with Egami's model. (C) 2011 Elsevier B.V. All rights reserved.
原文出处	://WOS:000292947500025
公开日期	2012-04-13
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/30660]
专题	金属研究所_中国科学院金属研究所
推荐引用方式 GB/T 7714	L. L. Shi,J. Xu. Mg based bulk metallic glasses: Glass transition temperature and elastic properties versus toughness[J]. Journal of Non-Crystalline Solids,2011,357(15):2926-2933.
APA	L. L. Shi,&J. Xu.(2011).Mg based bulk metallic glasses: Glass transition temperature and elastic properties versus toughness.Journal of Non-Crystalline Solids,357(15),2926-2933.
MLA	L. L. Shi,et al."Mg based bulk metallic glasses: Glass transition temperature and elastic properties versus toughness".Journal of Non-Crystalline Solids 357.15(2011):2926-2933.