Cold-temperature deformation of nano-sized tungsten and niobium as revealed by in-situ nano-mechanical experiments

作     者：LEE Seok-Woo CHENG YinTong RYU Ill GREER Julia R. 

作者机构：Division of Engineering and Applied Science California Institute of Technology School of Engineering Brown University 

出 版 物：《Science China(Technological Sciences)》 (中国科学（技术科学英文版）)

年 卷 期：2014年第57卷第4期

页      面：652-662页

核心收录：

学科分类：07[理学] 070205[理学-凝聚态物理] 08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：the financial support of the Kavli Nanoscience Institute (KNI) through LEE Seok-Woo’s prized post-doctoral fellowship, of the Keck Institute for Space Studies at Caltech, and of JRG’s NASA Early Career grant CHENG YinTong acknowledges the financial support of the Caltech SURF program 

主　　题：dislocation plasticity metal nanopillar cryogenics 

摘      要：We constructed and developed an in-situ cryogenic nanomechanical system to study small-scale mechanical behavior of materials at low temperatures. Uniaxial compression of two body-centered-cubic （bcc） metals, Nb and W, with diameters between 400 and 1300 rim, was studied at room temperature and at 165 K. Experiments were conducted inside of a Scanning Electron Microscope （SEM） equipped with a nanomechanical module, with simultaneous cooling of sample and diamond tip. Stress-strain data at 165 K exhibited higher yield strengths and more extensive strain bursts on average, as compared to those at 298 K. We discuss these differences in the framework of nano-sized plasticity and intrinsic lattice resistance. Dislocation dynamics simulations with surface-controlled dislocation multiplication were used to gain insight into size and temperature effects on deformation of nano-sized bcc metals.