点击次数：

论文类型：期刊论文

发表时间：2017-09-07

发表刊物：ACS APPLIED MATERIALS & INTERFACES

收录刊物：Scopus、SCIE、EI

卷号：9

期号：35

页面范围：29451-29456

ISSN号：1944-8244

关键字：in situ TEM; Ni alloy; nanoindentation; single nanotwin; slip

摘要：Nanotwinned (nt) materials exhibit excellent mechanical properties, and have been attracting much more attention of late. Nevertheless, the fundamental mechanism of interaction between dislocations and a single nanotwin is not understood. In this study, in situ transmission electron microscopy (TEM) nanoindentation is performed, on a specimen-of a nickel (Ni) alloy containing a single nanotwin of 89 nm in thickness. The specimen is prepared using focused ion beam (BIB) technique from an nt surface, which is formed by a novel approach-tinder indentation using a developed diamond panel with tips array. The stiffness of the specimen is ten times that-of the pristine counterparts during loading. The ultrahigh stiffness is attributed, to the generation of nanotwins and the impediment of the single twin. to the dislocations. Two peak loads-are induced by the activation of a new slip system and the penetration of dislocations over the single nanotwin, respectively. One slip band is parallel to the single nanotwin, indicating the slip of dislocations along the nanotwin. In situ TEM observation of nanoindentation reveals a new insight for the interaction between dislocations and a single nanotwin. This paves the way for design and preparation of high-performance nt surfaces of Ni alloys used for aircraft engines, gas turbines, turbocharger components, ducts, and absorbers.