非晶合金“拉伸转变区”模型

发布时间：2019-05-23 05:27

【摘要】：非晶合金是熔体深度过冷至玻璃态转变,结构发生突然"冻结"而形成的玻璃态固体.在远低于玻璃转变温度,非晶合金的宏观断裂通常由塑性变形局部化剪切带诱导.尽管非晶塑性机理还未完全揭示,但普遍认为剪切带模式的裂尖塑性流动源于材料内部原子集团的局部剪切重排,即"剪切转变区(shear transformation zone,STZ)"事件.但是,越来越多的工作表明,非晶合金的断裂并非总是由剪切带诱导,而呈现脆性的拉伸正断,并涌现出一种新的断裂面斑图:纳米周期条痕.针对这一全新的断裂能耗散过程,我们在2008年提出了非晶合金的"拉伸转变区(tension transformation zone,TTZ)"模型.本文将简要介绍非晶合金"拉伸转变区"模型的提出、内涵本质、激活条件、原子模拟和韧脆转变实验验证等,并对该模型的未来发展进行评述.
[Abstract]:Amorphous alloy is a glass solid formed by the deep undercooling of melt to glass state, and the structure is suddenly "frozen". When the glass transition temperature is much lower than the glass transition temperature, the macroscopic fracture of amorphous alloys is usually induced by the localized shear band of plastic deformation. Although the mechanism of amorphous plasticity has not been fully revealed, it is generally believed that the plastic flow at the crack tip of the shear band mode is due to the local shear rearrangement of atomic groups in the material, that is, the "shear transition zone (shear transformation zone,STZ" event. However, more and more work shows that the fracture of amorphous alloys is not always induced by shear band, but shows brittle tensile positive fracture, and a new fracture surface pattern, nanometer periodic stripe, has emerged. In view of this new process of fracture energy consumption dispersion, we proposed a "tensile transformation zone (tension transformation zone,TTZ" model for amorphous alloys in 2008. In this paper, the "tensile transformation zone" model of amorphous alloys is briefly introduced, including its connotation, essence, activation conditions, atomic simulation and experimental verification of ductile-brittle transition, etc., and the future development of the model is reviewed.
【作者单位】：中国科学院力学研究所非线性力学国家重点实验室;中国科学院大学工程科学学院;
【基金】：国家自然科学基金优秀青年科学基金(11522221)、国家自然科学基金(11372315,11472287) 中国科学院前沿科学重点研究项目(QYZDJSSW-JSC011)和中国科学院战略性先导科技专项(B类)(XDB22040303)
【分类号】：TG139.8

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