skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Synthesis, Microstructure, and Mechanical Properties of FeCo-VC Composites

Abstract

Fe-Co-V-C quaternary alloys were drop cast and directionally solidified to obtain an in situ composite. It is found that the fully eutectic structure occurs at a composition of Fe - 40.5Co -10.4V- 8.6C (at. %) in a drop-cast alloy. Directional solidification of this composition in a high-temperature optical floating zone furnace produces a well-aligned microstructure, consisting of sub-micron VC fibers ({approx}19% by volume) embedded in a FeCo-5V solid solution matrix containing {approx}1% C. The temperature dependencies of mechanical properties of this composite were examined by tensile tests and the composite was found to have higher yield strength and lower ductility than the matrix.

Authors:
 [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
931494
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: MRS Fall Meeting, Boston, MA, USA, 20061127, 20061201
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALLOYS; DUCTILITY; EUTECTICS; FIBERS; FURNACES; MECHANICAL PROPERTIES; MICROSTRUCTURE; SOLID SOLUTIONS; SOLIDIFICATION; SYNTHESIS; YIELD STRENGTH; COMPOSITE MATERIALS

Citation Formats

Bei, Hongbin, and George, Easo P. Synthesis, Microstructure, and Mechanical Properties of FeCo-VC Composites. United States: N. p., 2007. Web.
Bei, Hongbin, & George, Easo P. Synthesis, Microstructure, and Mechanical Properties of FeCo-VC Composites. United States.
Bei, Hongbin, and George, Easo P. Mon . "Synthesis, Microstructure, and Mechanical Properties of FeCo-VC Composites". United States. doi:.
@article{osti_931494,
title = {Synthesis, Microstructure, and Mechanical Properties of FeCo-VC Composites},
author = {Bei, Hongbin and George, Easo P},
abstractNote = {Fe-Co-V-C quaternary alloys were drop cast and directionally solidified to obtain an in situ composite. It is found that the fully eutectic structure occurs at a composition of Fe - 40.5Co -10.4V- 8.6C (at. %) in a drop-cast alloy. Directional solidification of this composition in a high-temperature optical floating zone furnace produces a well-aligned microstructure, consisting of sub-micron VC fibers ({approx}19% by volume) embedded in a FeCo-5V solid solution matrix containing {approx}1% C. The temperature dependencies of mechanical properties of this composite were examined by tensile tests and the composite was found to have higher yield strength and lower ductility than the matrix.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • SiC fiber-reinforced ZrTiO4 matrix composites were fabricated to study the effect of hot-pressing atmosphere (CO vs argon) on the mechanical properties and interfacial microstructure of the resultant composites. The effect of using CO heat-treated BN-coated Tyranno fibers as compared to untreated BN-coated Tyranno fibers was also investigated. Composites hot-pressed in CO with BN-coated Nicalon fibers resulted in a strong (960 MPa) and tough material. Composites hot-pressed with CO heat-treated BN-coated Tyranno fibers indicated that the microstructure of the heat-treated fibers was retained after processing. 14 refs.
  • An investigation is conducted of the effects of braze processing on the microstructure and tensile properties of SiC fiber-reinforced Ti-15Mo-2.7Nb-3Al-0.25Si-matrix composite (TMC) laminates; the brazing alloy was the commercial Ti-15Cu-15Ni, in both its conventional and metglass forms. Tensile tests conducted at room temperature, 1200 F, and 1500 F showed that the braze processes (1) had little effect on tensile properties, and (2) appeared to degrade neither the reinforcing fibers not the fiber/matrix interfacial bondline. 8 refs.
  • Quasi-carbon fibers (QCFs) were prepared from Polyacrylonitrile (PAN) precursor by pyrolysis in the temperature range from 400{degrees}C to 950{degrees}C. The QCF-reinforced composites were fabricated by impregnating the QCFs with the PAN resin. The microstructural changes of both QCFs and their composites were characterized by the X-ray diffraction method. The stacking size and the crystallinity of the QCFs increased with the increasing heat treatment temperature (HTT). The crystallinity of the PAN matrix in a composite was also affected by various QCFs. DSC data indicated that thermal reaction mechanism of the composite could be altered due to the interaction between the fibermore » and the matrix. DMTA studies showed that good adhesion existed at the interface of the QCF-reinforced composites containing lower HTT fibers. The modulus magnitudes of QCFs and their composites increased with the QCF pyrolysis temperature. Although the QCFs exhibited a decreasing trend in strength up to a pyrolysis temperature 650{degrees}C, the strength of the resulting composites increased monotonically. Thus, the QCF-reinforced composites exhibited good mechanical properties despite the fact that a catastrophic failure mode was observed with the QCF that was heat-treated above 650{degrees}C.« less
  • Microstructure effects on mechanical properties were investigated for SiC particulate reinforced MoSi{sub 2} composites. These composites were prepared by hot-pressing mixtures of sub-micron MoSi{sub 2} and nano-sized SiC powders at 1300 to 1800{degrees}C in Ar atmosphere. The microstructure of MoSi{sub 2}-based composites consisted of MoSi{sub 2}, SiC and small amounts of Mo{sub 5}Si{sub 3} and Mo{sub 2}C. Transmission electron microscopic observation revealed that the nano-sized {beta}-SiC particles were dispersed at the grain boundaries and also within the MoSi{sub 2} matrix grains. The fracture strength and toughness were considerably improved by the SiC dispersions. The MoSi{sub 2}/15vol%SiC composite hot-pressed at 1500{degrees}Cmore » gave the maximum strength of 1215 MPa. The enhancement of fracture strength in this system was mainly caused by the grain growth inhibition by the SiC dispersion. Moreover, the intergranular SiC particles played important roles to control the grain boundary structure by connecting directly with the matrix MoSi{sub 2} grains without impurity phases.« less
  • Alumina-based ceramic composites which second phases have a microstructure of equiaxed grains as YAG or elongated grains as LaAl11O18 by reaction of Al{sub 2}O{sub 3} and additives during hot-pressing, were fabricated using particulate-precipitated dispersion. The Al{sub 2}O{sub 3}/SiC/YAG hybrid composites having the equaxied second phase were fabricated in the temperature range from 1000 to 1800{degrees}C using SiC and Y{sub 2}O{sub 3} powders as additive. Then, YAG (yttrium aluminum garnet, Y3Al5O12) phase was formed as the second phase from the reaction between Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} above 1400{degrees}C hot-pressing temperature. The grain size of monolithic Al{sub 2}O{sub 3}more » increased with increasing hot-pressing temperature and hot-pressing time, while that of Al{sub 2}O{sub 3} increased with increasing hot-pressing temperature and hot-pressing time, while that of Al{sub 2}O{sub 3}/SiC/YAG hybrid composites was effectively restrained due to the incorporation of YAG and SiC particulate into Al{sub 2}O{sub 3} matrix. Also, Al{sub 2}O{sub 3}/LBA(lanthanum-{beta}-alumina, LaAl11O18) composites having an elongated second phase were successfully fabricated using Al{sub 2}O{sub 3} powder as additives. The properties of hot-pressed bodies, such as microstructural observation by SEM & TEM, phase analysis by XRD, strength, toughness, toughening mechanism etc., were investigated. The mechanical properties of flexural strength and fracture toughness of composites were higher than that of monolithic Al{sub 2}O{sub 3}. Also, the composites having elongated grains showed higher toughness due to grain bridging than the composites having equaxied second phase.« less