Modulus and Hardness Change of Silicon and Sapphire Substrates by TiC/VC Multilayer Coatings

作     者：Andre Belger Marianne Reibold Peter Paufler 

作者机构：On Leave from Institut für StrukturphysikTechnische Universitat DresdenDresdenGermany Triebenberg LaboratoryInstitut fur StrukturphysikTechnische Universitat DresdenDresdenGermany Institut fur StrukturphysikTechnische Universitat DresdenDresdenGermany 

出 版 物：《Materials Sciences and Applications》 (材料科学与应用期刊（英文）)

年 卷 期：2012年第3卷第4期

页      面：185-194页

学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

基　　金：thank the German Research Foundation(DFG)for financial support 

主　　题：TiC/VC@Si or Sapphire Multilayers Superlattice Effect X-Ray Absorption Spectrometry Electron Microscopy 

摘      要：The nanohardness H of multilayer specimens TiC/VC@Si and TiC/VC@Sapphire prepared by Pulsed-Laser-Deposition is investigated to check the existence of a superlattice effect as known from TiN/VN multilayers. In the present work the multilayer period thickness λ varies between 1.34 nm and 24.8 nm (total layer thickness t ≈ 200 nm). Unlike Young’s modulus E, H is enhanced, regardless of t, by covering Si as well as sapphire with a TiC/VC multilayer;the relative load carrying capacity being larger for Si. The maximum value of H obtained is 38 GPa for TiC/VC@Sapphire. It is observed for a multilayer thickness of λ ≈ 10 nm. Hardness of TiC/VC@Sapphire obeys, after annealing, a Hall-Petch relation H = 35.25 + 6.945 λ–0.5 (H in GPa und λ≥ 10 nm). From orientation dependent X-ray absorption fine structure and X-ray reflection records, short-range order and layer geometry are derived. These analyses reveal a continuous approach of interatomic distances Ti-C and V-C for deceasing multilayer periods. High-resolution transmission electron microscopy shows that multilayers are nanostructured, i.e., not only TiC/VC phase boundaries but also subgrains represent obstacles against plastic deformation. Dislocations play a major role as sources of internal stress and vehicles of plasticity.