文献类型：期刊文献

英文题名：Effect of overheating temperature on the microstructure and creep behavior of HP40Nb alloy

作者：Wang, W. Z.[1];Xuan, F. Z.[1];Wang, Z. D.[1];Wang, B.[1];Liu, C. J.[1]

机构：[1]E China Univ Sci & Technol, Key Lab Safety Sci Pressurized Syst, Minist Educ, Sch Mech & Power Engn, Shanghai 200237, Peoples R China

年份：2011

卷号：32

期号：7

起止页码：4010

外文期刊名：MATERIALS & DESIGN

收录：;EI(收录号：20111713942216);WOS:【SCI-EXPANDED(收录号:WOS:000291125100042)】；

基金：The authors gratefully appreciate the support of National Natural Science Foundation (No. 50805048), National High Technology Research and Development Program of China (863 Program) (No. 2009AA04Z421), Young Teacher Foundation of Education Ministry of China (No. 200802511008), Shanghai Rising-Star Program (10QA1401500), the Fundamental Research Funds for the Central Universities, Shanghai Key Technologies R & D Program (09521101304) and Shanghai Leading academic discipline project (B503).

语种：英文

外文关键词：Transmission electron microscopy - Niobium alloys - Petrochemical plants - Scanning electron microscopy - Creep - High temperature effects - Microstructure

摘要：HP40Nb alloy has been widely used as a high temperature material in petrochemical plants. However, overheating or local temperature excursion occurs occasionally in service and leads to serious damage on the material. Effect of temperature on the microstructure and creep performance of the HP40Nb alloy is investigated in the present work. Several specimens are cut from serviced components of the alloy and heat-treated at different temperatures from 900 degrees C to 1250 degrees C for its possible working conditions, in which the temperature of 1200 or 1250 degrees C is used to simulate the overheating condition of HP40Nb tubes. The microstructure of specimens is examined by scanning electron microscope (SEM) and transmission electron microscope (TEM). The creep behavior is evaluated through using impression creep tests with a flat-ended cylindrical indenter. The content of inter- and intra-dendritic carbides in the specimens is represented by the surface fraction of each phase, which has been estimated by image processing method. The results show that the total of the surface fraction of inter- and intra-dendritic carbides in the HP40Nb alloy does not significantly change at the temperature lower than 1100 degrees C. However, the surface fraction of inter-dendritic carbides reaches the maximum at 1100 degrees C. A maximal steady state impression rate is also observed at 1100 degrees C. The results suggest that the content of inter-dendritic carbides is the main influencing factor on the creep performance of HP40Nb alloys comparing with that of the intra-dendritic carbides. (C) 2011 Elsevier Ltd. All rights reserved.