Published August 2018 | Version v1
Journal article Metadata-only

Secondary phases formation in lanthanum-doped titanium-zirconium-molybdenum alloy

Creators

  • 1. National and Local Joint Engineering Research Functional Center for Materials Processing, Xi' an University of Architecture and Technology, Xi'an 710055 (China)
  • 2. School of Metallurgy Engineering, Xi'an University of Architecture and Technology, Xi'an 710055 (China)
  • 3. Jinduicheng Molybdenum Co., Ltd., Xi'an 710077 (China)
  • 4. Department of Mechanical Engineering, University of South Florida, Tampa FL 33620 (United States)
  • 5. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 (China)

Description

Highlights: • Formation process of second phases in La-TZM alloy calculated by thermodynamics. • The Delta G of TiO2, ZrO2, ZrC, TiC, ZrTiO4, MoO3 and MoC are negative. • TG-MS, XRD, SEM, TEM show the process and second phase in La-TZM alloy. • Secondary phases include TiO2, ZrO2, ZrC, TiC, MoC, ZrTiO4, La2O3 and Ti/Zr solid phase. Lanthanum-doped titanium-zirconium-molybdenum (La-TZM) alloys have good mechanical properties, including high strength and toughness due to complex secondary phases. Herein, the formation process of the secondary phases in the La-TZM alloy was revealed by thermodynamics calculations. The ΔG values of possible reactions during sintering were obtained. Results show that the formation process of the secondary phases was controlled by different reactions at different stages. At the first stage (0–500 °C), the main reactions are listed as follows: TiH2+O2(g)→TiO2+H2↑(g), ZrH2+O2(g)→ZrO2+H2↑(g), C6H12O6→[C]+ H2O↑, [C]+ O2(g)→CO2(g)↑, [C]+Mo→MoC, La(NO3)3·6H2O→ La2O3+NO2↑+ NO↑+O2↑+H2O; [C]+TiH2→TiC + H2(g)↑, [C]+ZrH2→ZrC + H2(g)↑. At the secondary stage (680–960 °C), the dominant reactions include: TiH2→Ti + H2(g)↑, ZrH2→Zr + H2(g)↑. At the last stage (≥1200 °C), the primary reaction is Ti + Zr+[O]→ZrTiO4. The secondary phases in the La-TZM alloy include TiO2, ZrO2, ZrC, TiC, MoC, ZrTiO4, La2O3 and the solid Ti and Zr phases. These results can guide the design of new ingredients for Mo alloys.

Availability note (English)

Available from http://dx.doi.org/10.1016/j.jallcom.2018.05.103

Additional details

Identifiers

DOI
10.1016/j.jallcom.2018.05.103;
PII
S0925838818317882;

Publishing Information

Journal Title
Journal of Alloys and Compounds
Journal Volume
757
Journal Page Range
p. 340-347
ISSN
0925-8388
CODEN
JALCEU

INIS

Country of Publication
Switzerland
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
53080190
Subject category
S36: MATERIALS SCIENCE;
Descriptors DEI
ALLOY-MO99; CARBON DIOXIDE; DOPED MATERIALS; LANTHANUM; LANTHANUM OXIDES; MECHANICAL PROPERTIES; MOLYBDENUM; MOLYBDENUM CARBIDES; MOLYBDENUM OXIDES; NITROGEN DIOXIDE; SCANNING ELECTRON MICROSCOPY; THERMODYNAMICS; TITANIUM CARBIDES; TITANIUM HYDRIDES; TITANIUM OXIDES; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; ZIRCONIUM CARBIDES; ZIRCONIUM HYDRIDES; ZIRCONIUM OXIDES
Descriptors DEC
ALLOYS; CARBIDES; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; COHERENT SCATTERING; CORROSION RESISTANT ALLOYS; DIFFRACTION; ELECTRON MICROSCOPY; ELEMENTS; HEAT RESISTANT MATERIALS; HEAT RESISTING ALLOYS; HYDRIDES; HYDROGEN COMPOUNDS; LANTHANUM COMPOUNDS; MATERIALS; METALS; MICROSCOPY; MOLYBDENUM ALLOYS; MOLYBDENUM BASE ALLOYS; MOLYBDENUM COMPOUNDS; NITROGEN COMPOUNDS; NITROGEN OXIDES; OXIDES; OXYGEN COMPOUNDS; RARE EARTH COMPOUNDS; RARE EARTHS; REFRACTORY METAL COMPOUNDS; REFRACTORY METALS; SCATTERING; TITANIUM ADDITIONS; TITANIUM ALLOYS; TITANIUM COMPOUNDS; TRANSITION ELEMENT ALLOYS; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS; ZIRCONIUM ADDITIONS; ZIRCONIUM ALLOYS; ZIRCONIUM COMPOUNDS

Optional Information

Copyright
Copyright (c) 2018 Elsevier B.V. All rights reserved.