Details

Autor(en) / Beteiligte

• Nie, Anmin
• Bu, Yeqiang
• Huang, Junquan
• Shao, Yecheng
• Zhang, Yizhi
• Hu, Wentao
• Liu, Jiabin
• Wang, Yanbin
• Xu, Bo
• Liu, Zhongyuan
• Wang, Hongtao
• Yang, Wei
• Tian, Yongjun

Titel

Direct Observation of Room-Temperature Dislocation Plasticity in Diamond

Ist Teil von

• Matter, 2020-05, Vol.2 (5), p.1222-1232

Ort / Verlag

Elsevier Inc

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• It is well known that diamond does not deform plastically at room temperature and usually fails in catastrophic brittle fracture. Here, we demonstrate room-temperature dislocation plasticity in submicrometer-sized diamond pillars by in situ mechanical testing under the transmission electron microscope. We document in unprecedented details of spatiotemporal features of the dislocations introduced by the confinement-free compression, including dislocation generation and propagation. Atom-resolved observations with tomographic reconstructions show unequivocally that mixed-type dislocations with Burgers vectors of 1/2 are activated in the non-close-packed {001} planes of diamond under uniaxial compression of and directions, respectively, while being activated in the {111} planes under the directional loading, indicating orientation-dependent dislocation plasticity. These results provide new insights into the mechanical behavior of diamond and stimulate reconsideration of the basic deformation mechanism in diamond as well as in other brittle covalent crystals at low temperatures. [Display omitted] •Dislocation mediated plastic deformation of diamond is observed at room temperature•Dislocations are activated in the non-close-packed {001} planes of diamond•Dislocation behaviors in diamond show obvious orientation dependence•The dislocation structures in diamond are well demonstrated Despite exceptionally high strength and hardness, diamond is extremely brittle at room temperature. Room-temperature plasticity has rarely been observed experimentally and is generally considered unlikely to occur because of the domination of catastrophic brittle fracture in diamond. Here, through in situ mechanical testing under the transmission electron microscope, we demonstrate dislocation plasticity in diamond nanopillars at room temperature, with clearly resolved spatiotemporal features of dislocation generation and propagation. Our direct observations provide unequivocal experimental evidence and new insight into the mechanical properties of diamond, settling the long-standing controversy of plasticity in diamond at room temperature. The orientation-dependent dislocation behaviors observed in diamond, especially generation in the non-close-packed {001} planes, stimulate reconsideration of the basic deformation mechanism of the brittle covalent crystals at low temperatures.