AuAg纳米晶薄膜裂纹扩展的原位原子尺度观察

AuAg纳米晶薄膜裂纹扩展的原位原子尺度观察

杨成鹏，符立波，郭谊忠，王立华^∗，张 泽^∗，韩晓东^∗

（1. 北京工业大学固体微结构与性能研究所，北京市先进材料微结构与性能重点实验室，北京100124；2. 浙江大学材料科学与工程学院，浙江杭州310008）

摘  要 本文利用原位实验技术，在透射电镜中对AuAg纳米晶薄膜裂纹扩展以及裂纹前端塑性机制进行了原位原子尺度观察。原位观察发现，在初期，裂纹在晶界处形核并沿着晶界扩展，在裂纹前端晶粒内部有形变孪晶的形核与长大。随着应变的增加，逐渐转为穿晶断裂，此时晶粒内的生长孪晶及变形孪晶均展现出良好的塑性变形能力。本实验对人们理解面心立方合金纳米晶材料的裂纹扩展机制具有一定借鉴意义。

关键词   纳米晶薄膜；裂纹扩展；晶间裂纹；合金；退孪晶；孪晶

中图分类号：TB383；O733; TG115. 5⁺2; TG115. 21⁺5. 3

文献标识码：Adoi:10.3969/j.issn.1000-6281.2021.05.001

In situ atomic-scale observation of crack propagation in AuAg nanocrystalline films

YANG Cheng-peng¹，FU Li-bo¹，GUO Yi-zhong¹，WANG Li-hua^1*，ZHANG Ze^1，2*，HAN Xiao-dong^1*

(1. Beijing Key Lab of Microstructure and Property of Advanced Material, Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124; ；2. Department of Materials Science, Zhejiang University, Hangzhou Zhejiang 310008, China)

Abstract   Using home-made techniques, the atomic-scale crack propagation progress of AuAg nanocrystalline film was in-situ captured. The results showed that at the early stage of crack propagation, the crack nucleates and propagates along the grain boundary. This process also was accompanied by deformation twin nucleation and growth of the grain at the front of the crack tip. With the tensile strain increasing, the crack turns to the transgranular fracture mode, in which the plasticity was governed by detwinning. Our results also show that both growth twin and deformation twin in the grain can enhance the ductility of nanocrystalline alloys.

Keywords   nanocrystalline film;；crack propagation;；intergranular crack;；detwinning;；alloy;；twin

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[1] MEYERS M A，MISHRA A，BENSON D J. Mechanical properties of nanocrystalline materials [J]. Progress in Materials Science, 2006，51(4): 427-556.

[2] LU K，LU L，SURESH S. Strengthening materials by engineering coherent internal boundaries at the nanoscale [J]. Science，2009，324: 349-352.

[3] KE X，YE J，PAN Z，et al. Ideal maximum strengths and defect-induced softening in nanocrystalline-nanotwinned metals [J]. Nature Materials，2019，18(11): 1207-1214.

[4] SCHUH C A，NIEH T G，YAMASAKI T. Hall–Petch breakdown manifested in abrasive wear resistance of nanocrystalline nickel [J]. Scripta Materialia，2002，46(10): 735–740. 

[5] HANLON T. Grain size effects on the fatigue response of nanocrystalline metals [J]. Scripta Materialia，2003，49(7): 675-680.

[6] SUN Y, ROGERS J A. Inorganic semiconductors for flexible electronics [J]. Advanced Materials, 2007, 19(15): 1897-1916.

[7] BÉFAHY S，YUNUS S，PARDOEN T，et al. Stretchable helical gold conductor on silicone rubber microwire [J]. Applied Physics Letters, 2007, 91(14):141911.

[8] LACOUR S P，WAGNER S，HUANG Z，et al. Stretchable gold conductors on elastomeric substrates [J]. Applied Physics Letters, 2003，82(15): 2404-2406.

[9] IKER F，ANDRE N，PARDOEN T，et al. Three-dimensional self-assembled sensors in thin-film SOI technology [J]. Journal of Microelectromechanical Systems，2006，15: 1687-1697.

[10] WANG Y, CHEN M.  High tensile ductility in a nanostructured metal [J]. Nature, 2002, 419(6910): 912-915.

[11] EVANS A，HE M，HUTCHINSON J. Effect of interface undulations on the thermal fatigue of thin films and scales on metal substrates [J]. Acta Materialia，1997，45(9): 3543–3554

[12]马莹，卢艳，孔德利，等.  单晶钽裂纹尖端的位错原位观察[J]. 电子显微学报，2017，36(4): 306-312.

[13]姜文全，昝静一，杨 帆，等. 铜薄膜内微孔对其力学性能影响及开裂行为研究[J]. 电子显微学报，2017，36(5): 436-441.

[14] 马一鸣，李珊，杨晓京. 单晶锗同晶面不同取向对脆塑转变影响的实验研究[J]. 电子显微学报，2020，39(4): 1000-6281.

[15] WANG H T, YANG W. Constitutive modeling for nanocrystalline metals based on cooperative grain boundary mechanisms [J]. Journal of the Mechanics and Physics of Solids, 2004, 52(5): 1151-1173.

[16] YANG W, WANG H T. Mechanics modeling for deformation of nano-grained metals [J]. Journal of the Mechanics and Physics of Solids，2004, 52(4): 875–889.

[17] FARKAS D, VAN SWYGENHOVEN H, DERLET P M. Intergranular fracture in nanocrystalline metals [J]. Physical Review B, 2002，66(6): 340-351.

[18] CUI J P，HAO Y L，LI S J, et al. Reversible movement of homogenously nucleated dislocations in a-titanium alloy [J]. Physical Review Letters, 2009, 102(4): 045503.

[19] YANG F, YANG W. Brittle versus ductile transition of nanocrystalline metals [J]. Int J Solids Struct，2008，45: 3897–907.

[20] 郭谊忠，王立华，张泽，等. 单晶Pt裂纹前端位错行为的原位原子尺度观察[J]. 电子显微学报，2019，38(5): 1000-6281.

[21] 孙涛，郭谊忠，符立波，等. 孪晶结构Pt纳米晶体塑性变形行为的原位原子尺度观察[J]. 电子显微学报，2020，39(2): 101-105.