Study of Chemical Inhomogeneity in Beta-Solidifying TiAl Alloys of Various Composition

Metallurgist ◽  
2021 ◽  
Vol 64 (9-10) ◽  
pp. 962-973
Author(s):  
A. S. Kochetkov ◽  
P. V. Panin ◽  
N. A. Nochovnaya ◽  
M. A. Makushina
Author(s):  
Ernest L. Hall ◽  
Shyh-Chin Huang

Addition of interstitial elements to γ-TiAl alloys is currently being explored as a method for improving the properties of these alloys. Previous work in which a number of interstitial elements were studied showed that boron was particularly effective in refining the grain size in castings, and led to enhanced strength while maintaining reasonable ductility. Other investigators have shown that B in γ-TiAl alloys tends to promote the formation of TiB2 as a second phase. In this study, the microstructure of Bcontaining TiAl alloys was examined in detail in order to describe the mechanism by which B alters the structure and properties of these alloys.


Author(s):  
T. Egami ◽  
H. D. Rosenfeld ◽  
S. Teslic

Relaxor ferroelectrics, such as Pb(Mg1/3Nb2/3)O3 (PMN) or (Pb·88La ·12)(Zr·65Ti·35)O3 (PLZT), show diffuse ferroelectric transition which depends upon frequency of the a.c. field. In spite of their wide use in various applications details of their atomic structure and the mechanism of relaxor ferroelectric transition are not sufficiently understood. While their crystallographic structure is cubic perovskite, ABO3, their thermal factors (apparent amplitude of thermal vibration) is quite large, suggesting local displacive disorder due to heterovalent ion mixing. Electron microscopy suggests nano-scale structural as well as chemical inhomogeneity.We have studied the atomic structure of these solids by pulsed neutron scattering using the atomic pair-distribution analysis. The measurements were made at the Intense Pulsed Neutron Source (IPNS) of Argonne National Laboratory. Pulsed neutrons are produced by a pulsed proton beam accelerated to 750 MeV hitting a uranium target at a rate of 30 Hz. Even after moderation by a liquid methane moderator high flux of epithermal neutrons with energies ranging up to few eV’s remain.


2011 ◽  
Vol 1295 ◽  
Author(s):  
Marc Thomas

ABSTRACTOne of the main driving force for the development of advanced structural materials is weight saving especially in the transportation industry in order to reduce CO2 emission. The utilization of gamma aluminides, as good candidates for aerospace applications, is strongly related to the development of a cost-effective and robust processing route, as far as possible. It is well established that the processing route, i.e. cast, wrought or PM, has a dramatic effect on the microstructure and texture of gamma-TiAl alloys. Therefore, significant microstructural variations through post-heat treatments coupled with compositional modifications can only guarantee a proper balance of desired properties. However, a number of metallurgical factors during the processing steps can contribute to some scattering in properties. This review will highlight several critical process variables in terms of the resulting g-TiAl microstructures. Of primary importance is the as-cast texture which is difficult to control and may contribute to prefer some alternative processing routes to ensure a better repeatability in mechanical results. Some innovative processing techniques for controlling the structure will then be presented. The main point which will be discussed in this paper is whether an approach leading to a robust process would not be at the expense of the high performance of the structural material.


2014 ◽  
Vol 43 (3) ◽  
pp. 540-543 ◽  
Author(s):  
Zhe Wang ◽  
Rui Cao ◽  
Jianhong Chen ◽  
Ji Zhang

2012 ◽  
Vol 212 (9) ◽  
pp. 1934-1940 ◽  
Author(s):  
Ruirun Chen ◽  
Jieren Yang ◽  
Hongsheng Ding ◽  
Feng Huang ◽  
Yanqing Su ◽  
...  

2019 ◽  
Vol 11 (15) ◽  
pp. 37-48 ◽  
Author(s):  
Patrick J. Masset ◽  
Michael Schütze

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