Nitridation of Ni-based alloys:thermodynamics,kinetics,and deformation phenomena accompanying internal precipitation

作     者：Alexander A.Kodentsov Jorma K.Kivilahti Frans J.J.van Loo 

作者机构：Laboratory of Materials and Interface ChemistryEindhoven University of TechnologyP.O.Box 5135600 MBEindhovenThe Netherlands Laboratory of Electronics Production TechnologyHelsinki University of TechnologyFIN-02150 EspooFinland 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2006年第25卷第5期

页      面：501-511页

核心收录：

学科分类：07[理学] 070205[理学-凝聚态物理] 0702[理学-物理学] 

主　　题：nitridation nickel alloys thermodynamics diffusion internal precipitation 

摘      要：When a moderately stable phase is precipitated out during an intemal reaction, the behaviour of the penetrating atoms within the diffusion zone can be interpreted based on thermodynamic considerations. Evidence for “up-hill diffusion of the penetrating species through the matrix towards the precipitation front during the intemal nitridation of Ni-Cr alloys at 1125℃ and 6000 bar of N2-pressure was predicted. Such behaviour of nitrogen is opposite to the boundary conditions in Wagner＇s description of internal reactions. A volume change associated with the precipitation reaction resulted in a stress gradient between the alloys surface and the intemal nitridation front. Stress relief occurred mainly by transport of nickel to the gas/metal interface. Pipe diffusion-controlled creep is the dominant stress accommodation mechanism during nitriding of dilute Ni-Cr alloys at 700℃ under a flowing NH3 ＋ H2 gas mixture.