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Title: Microstructural characterization of near-[alpha] titanium alloy Ti-6Al-4Sn-4Zr-0. 70Nb-0. 50Mo-0. 40Si

Abstract

Microstructural stability in the near-[alpha] titanium alloy (alloy 834) containing Ti-6Al-4Sn-4Zr-0.7ONb-0.5OMo-0.4OSi (in weight percent), in the [beta] and ([alpha] + [beta]) solution-treated and quenched conditions, has been investigated. The [beta] transus for this alloy is approximately 1,333 K. Solution treatment in the [beta] phase field at 1,353 K followed by quenching in water at room temperature resulted in the formation of [alpha][prime] martensite platelets with high dislocation density and stacking faults. Thin films of [beta] are found to be sandwiched between interface phases, which, in turn, are sandwiched at the interplatelet boundaries of lath martensite. The interface phase is a subject of much controversy in the literature. Solution treatment at 1,303 K in the ([alpha] + [beta]) phase field followed by quenching in water at room temperature resulted in the near-equiaxed primary a and transformed [beta]. Both the [beta] and ([alpha] + [beta]) solution-treated specimens were aged in the temperature range of 873 to 973 K. While aging the G-treated specimen at 973 K, ([alpha] + [beta])-treated specimen, even at a lower temperature of 873 K for 24 hours, caused precipitation of silicides predominantly at the interplatelet boundaries of martensite laths. Electron diffraction analysis confirmed them to be hexagonal silicidemore » S[sub 2], with [alpha] = 0.702 nm and c = 0.36[sub 8] nm. The above difference in the precipitation could be attributed to the partitioning of a higher amount of [beta]- stabilizing elements as well as silicide-forming elements to the transformed [beta] in the ([alpha] + [beta]) solution-treated condition. However, ordering of the [alpha][prime] phase was observed under all of the aging conditions studied. The ordered domains were due to the longer aging times, which cause local increases in the level of the [alpha]-stabilizing elements.« less

Authors:
; ;  [1]
  1. Baranas Hindu Univ., (India). Department of Metallurgical Engineering
Publication Date:
OSTI Identifier:
6311701
Resource Type:
Journal Article
Journal Name:
Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)
Additional Journal Information:
Journal Volume: 24A:6; Journal ID: ISSN 0360-2133
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ALLOYS; MICROSTRUCTURE; TIN ALLOYS; TITANIUM BASE ALLOYS; ZIRCONIUM ALLOYS; AGING; ELECTRON DIFFRACTION; HEAT TREATMENTS; INTERFACES; MARTENSITE; MOLYBDENUM ADDITIONS; NIOBIUM ADDITIONS; PHASE STUDIES; PHASE TRANSFORMATIONS; PRECIPITATION; QUENCHING; SILICIDES; SILICON ADDITIONS; TEMPERATURE RANGE 0400-1000 K; THIN FILMS; ALLOYS; CARBON ADDITIONS; COHERENT SCATTERING; DIFFRACTION; FILMS; IRON ALLOYS; MOLYBDENUM ALLOYS; NIOBIUM ALLOYS; SCATTERING; SEPARATION PROCESSES; SILICON ALLOYS; SILICON COMPOUNDS; TEMPERATURE RANGE; TITANIUM ALLOYS; 360102* - Metals & Alloys- Structure & Phase Studies

Citation Formats

Ramachandra, C, Singh, A K, and Sarma, G M.K. Microstructural characterization of near-[alpha] titanium alloy Ti-6Al-4Sn-4Zr-0. 70Nb-0. 50Mo-0. 40Si. United States: N. p., 1993. Web. doi:10.1007/BF02668196.
Ramachandra, C, Singh, A K, & Sarma, G M.K. Microstructural characterization of near-[alpha] titanium alloy Ti-6Al-4Sn-4Zr-0. 70Nb-0. 50Mo-0. 40Si. United States. https://doi.org/10.1007/BF02668196
Ramachandra, C, Singh, A K, and Sarma, G M.K. 1993. "Microstructural characterization of near-[alpha] titanium alloy Ti-6Al-4Sn-4Zr-0. 70Nb-0. 50Mo-0. 40Si". United States. https://doi.org/10.1007/BF02668196.
@article{osti_6311701,
title = {Microstructural characterization of near-[alpha] titanium alloy Ti-6Al-4Sn-4Zr-0. 70Nb-0. 50Mo-0. 40Si},
author = {Ramachandra, C and Singh, A K and Sarma, G M.K.},
abstractNote = {Microstructural stability in the near-[alpha] titanium alloy (alloy 834) containing Ti-6Al-4Sn-4Zr-0.7ONb-0.5OMo-0.4OSi (in weight percent), in the [beta] and ([alpha] + [beta]) solution-treated and quenched conditions, has been investigated. The [beta] transus for this alloy is approximately 1,333 K. Solution treatment in the [beta] phase field at 1,353 K followed by quenching in water at room temperature resulted in the formation of [alpha][prime] martensite platelets with high dislocation density and stacking faults. Thin films of [beta] are found to be sandwiched between interface phases, which, in turn, are sandwiched at the interplatelet boundaries of lath martensite. The interface phase is a subject of much controversy in the literature. Solution treatment at 1,303 K in the ([alpha] + [beta]) phase field followed by quenching in water at room temperature resulted in the near-equiaxed primary a and transformed [beta]. Both the [beta] and ([alpha] + [beta]) solution-treated specimens were aged in the temperature range of 873 to 973 K. While aging the G-treated specimen at 973 K, ([alpha] + [beta])-treated specimen, even at a lower temperature of 873 K for 24 hours, caused precipitation of silicides predominantly at the interplatelet boundaries of martensite laths. Electron diffraction analysis confirmed them to be hexagonal silicide S[sub 2], with [alpha] = 0.702 nm and c = 0.36[sub 8] nm. The above difference in the precipitation could be attributed to the partitioning of a higher amount of [beta]- stabilizing elements as well as silicide-forming elements to the transformed [beta] in the ([alpha] + [beta]) solution-treated condition. However, ordering of the [alpha][prime] phase was observed under all of the aging conditions studied. The ordered domains were due to the longer aging times, which cause local increases in the level of the [alpha]-stabilizing elements.},
doi = {10.1007/BF02668196},
url = {https://www.osti.gov/biblio/6311701}, journal = {Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)},
issn = {0360-2133},
number = ,
volume = 24A:6,
place = {United States},
year = {1993},
month = {6}
}