首页|定向凝固条件下Ti3Al合金中梯度纳米结构的形成机制与力学行为——原子尺度研究

定向凝固条件下Ti3Al合金中梯度纳米结构的形成机制与力学行为——原子尺度研究

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通过分子动力学(MD)模拟方法对Ti3Al合金在定向凝固条件下的生长机理进行系统研究,并通过对比纳米晶(NG)、粗晶(CG)和梯度纳米晶(GNG)合金,研究Ti3Al合金的结构力学性能.结果表明,在凝固过程中Ti3Al相优先生长为等轴晶组织,随后逐渐演变为柱状粒,并最终形成梯度纳米晶结构.此时,晶粒在与凝固方向平行的方向优先生长.此外,研究还发现,相较于NG和CG结构,GNG结构定向凝固合金具有更高的抗拉强度和更好的延展性.GNG结构不仅有效抑制了小晶粒区域的应变局域化和晶粒生长,而且促进了较大晶粒区域的位错形成,从而获得更好的力学性能.
Formation mechanism and mechanical behavior of gradient nanograin structure in directional solidified Ti3Al alloy:Atomic-scale study
The formation mechanism of Ti3Al alloy during a directional solidification process was systemically investigated by means of molecular dynamics(MD)simulations,and its mechanical behavior was explored by comparing with its nanograined(NG),coarse-grained(CG)and gradient nanograined(GNG)counterparts.It is found that the solidified front forms equiaxed crystals first,then they transform into columnar crystals,and the GNG structure is formed finally.Noticeably,the grains will grow preferentially in the direction parallel to the solidification direction.Besides,it is also found that the directional solidified alloy with the GNG structure has higher tensile strength and better ductility than its NG and CG counterparts.The GNG structure not only suppresses strain localization and grain growth in its small grain regions,but also promotes more cross dislocations in the large grain regions,resulting in a better mechanical performance.

directional solidificationTi3Al alloymolecular dynamics simulationgradient nanograin structure

邹鹏飞、李昌、侯兆阳、Jia-yiSUN、高全华、李克凡、王真、Ke-junDONG

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长安大学理学院,西安 710064

Faculty of Natural,Mathematics & Engineering Sciences,King's College London,London,WC2R 2LS,United Kingdom

School of Engineering,Design and Built Environment,Western Sydney University,Penrith,NSW 2751,Australia

定向凝固 Ti3Al合金 分子动力学模拟 梯度纳米结构

国家自然科学基金Natural Science Basic Research Plan in Shaanxi ProvinceFundamental Research Funds for the Central Universities of CHDFundamental Research Funds for the Central Universities of CHD

522011032023JCYB445300102122201300102122106

2024

10.1016/S1003-6326(24)66487-3

中国有色金属学报(英文版)
中国有色金属学会

中国有色金属学报(英文版)

CSTPCD
影响因子：1.183
ISSN：1003-6326
年,卷(期)：2024.34(5)