Paper Title:
N--H Interaction in Nitrided Fe--Nb Alloys
  Abstract

Internal friction of nitrogen in α iron has known as Snoek peak of N atom resolv ed in the octahedral interstitial site of bcc. When M atom ( Mn, Mo, Si, et.al) which has the affinity bigger than Fe were added ,another peaks due to the jump of N from Fe-Fe site to Fe-M site appear in the upper temperature side and complicate the Snoek peak curve of N. In this paper, the Snoek peak curve was studied in Fe-0.4wt%Nb-0.02wt%N alloys. This alloy showed no other peaks in the upper side to 373K and had only the single peak of N in Fe-Fe site. Internal friction measured by torsion pendulum method at about 1 Hz. After that this alloy was cooled from 373K to room temperature and reheated to 373K, but Snoek peak of N which showed on the first measurement just after nitriding disappeared completely and internal friction was only background. One of the reasons of it is the precipitation of Fe16N2 under heating and resolved N atoms disappeared. So these specimens were reheated to 873K and quenched, but Snoek peak of N was not measured. This shows the disappearance of N atom from Fe-Fe site. The mixture gas of a few % NH3 and H2 was used in this study. Therefore after nitriding much of H atoms were resolved in α iron alloys. Because the diffusion rate of H atom in α iron is bigger than N atom , it expected that H atoms can combine with Nb atoms before coming N atoms. And the appearance of Snoek peak of N in these alloys is considered. After that, in the heating to 373K H atom leave Nb and go away from the surface, and N atoms combine with Nb in place of H atoms. Nb has the very strong affinity with N, so these alloys have no peaks. When they reheated to the nitriding temperature N atoms can not diffuse from Fe-Nb site to Fe-Fe site. Then Snoek peak of N can not appears again in these alloys. Therefore, when Fe-Nb alloys were nitrided in NH3 and H2 mixture gas H atom plays very important part and it needs that the interaction of N-H atoms will be considered in these nitrided Fe-Nb alloys.

  Info
Periodical
Materials Science Forum (Volumes 539-543)
Main Theme
Edited by
T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran
Pages
4987-4992
DOI
10.4028/www.scientific.net/MSF.539-543.4987
Citation
M. Sakamoto, "N--H Interaction in Nitrided Fe--Nb Alloys", Materials Science Forum, Vols. 539-543, pp. 4987-4992, 2007
Online since
March 2007
Export
Price
$35.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: A.A. Kodentsov, M.J.H. van Dal, Csaba Cserháti, Lajos Daróczi, F.J.J. van Loo
73
Authors: Yong Xue, Zhi Min Zhang, Li Hui Lang, Li Li
Abstract:In the present paper a research has been made on the effect of aging on the microstructure and mechanical properties of AZ80 and ZK60 wrought...
560
Authors: Hong Wei Liu, Yon Gan Zhang, Jian Bo Zhang, Bao Hong Zhu, Feng Wang, Zhi Hui Li, Xi Wu Li, Bai Qing Xiong
Chapter 1: Materials Properties
Abstract:Microstructural characterization of Al-Cu-Mg-Ag alloy ageing at low and elevated temperature were investigated by differential scanning...
1225
Authors: György Thalmaier, Ioan Vida-Simiti, N. Jumate, Viorel Aurel Şerban, C. Codrean, Mircea Nicoară, L. Bukkosi
Chapter 1: Advanced Materials
Abstract:Nickel–titanium- group 5A metal (V, Nb, Ta, Zr) alloys are known as promising hydrogen-selective membrane materials. They can potentially be...
41
Authors: Jung Hwa Seo, Dong Geun Lee, Cheng Lin Li, Xu Jun Mi, Yong Tae Lee
Chapter 1: Advanced Materials and Technology on Metallurgy
Abstract:Microstructure characterization and hardening behavior of a new designed Ti-12.1Mo-1Fe alloy during solution and aging treatment was...
37