Structure and mechanical properties of MoSi2-SiC nanolayer composites

Harriet Kung, Tom Jervis, Juha-Pekka Hirvonen, John Embury, Terry Mitchell, Michael Nastasi

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

A systematic study of the structure-mechanical properties relationship is reported for both single phase and nanolayer composites of MoSi2 and SiC.
Single phase or alternating layers of MoSi2 and SiC were synthesized by d.c.-magnetron and r.f.-diode sputtering, respectively.
Cross-sectional transmission electron microscopy was used to examine several distinct reactions in the specimens when annealed at progressively higher temperatures: crystallization and phase transformation of MoSi2, crystallization of SiC, layer spheroidization, and grain growth.
Nanoindentation was employed to characterize the mechanical response of the materials as a function of the structural changes. As-sputtered material exhibits an amorphous structure in both single phase and multilayer forms. Heat treatment induces similar recrystallization behaviour in MoSi2 in both single phase and multilayers. SiC, in single phase form, remains amorphous up to 900 degrees-1 h anneal, while in multilayers it starts to crystallize at 700 degrees C. Annealing at 900 degrees C for 2 h causes the spheroidization of the layering which results in the formation of a nanocrystalline equiaxed microstructure.
Abnormal grain growth is observed after the spheroidization. The crystallization process is directly responsible for the hardness and modulus increase in both single phase and multilayered films. A maximum hardness of 25.5 GPa and a modulus of 382 GPa can be achieved through crystallizing both MoSi2 and SiC layers.
Prolonged high temperature exposure causes hardness degradation due to grain growth but the modulus remains almost constant. The layered geometry offers better elastic properties (higher modulus) than the single phase films.
Original languageEnglish
Pages (from-to)759-779
JournalPhilosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties
Volume71
Issue number4
DOIs
Publication statusPublished - 1995
MoE publication typeA1 Journal article-refereed

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Crystallization
Grain growth
Multilayers
hardness
Hardness
mechanical properties
crystallization
Mechanical properties
composite materials
Composite materials
causes
Nanoindentation
nanoindentation
Sputtering
phase transformations
Diodes
heat treatment
elastic properties
sputtering
Phase transitions

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Kung, Harriet ; Jervis, Tom ; Hirvonen, Juha-Pekka ; Embury, John ; Mitchell, Terry ; Nastasi, Michael. / Structure and mechanical properties of MoSi2-SiC nanolayer composites. In: Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties. 1995 ; Vol. 71, No. 4. pp. 759-779.
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abstract = "A systematic study of the structure-mechanical properties relationship is reported for both single phase and nanolayer composites of MoSi2 and SiC. Single phase or alternating layers of MoSi2 and SiC were synthesized by d.c.-magnetron and r.f.-diode sputtering, respectively. Cross-sectional transmission electron microscopy was used to examine several distinct reactions in the specimens when annealed at progressively higher temperatures: crystallization and phase transformation of MoSi2, crystallization of SiC, layer spheroidization, and grain growth. Nanoindentation was employed to characterize the mechanical response of the materials as a function of the structural changes. As-sputtered material exhibits an amorphous structure in both single phase and multilayer forms. Heat treatment induces similar recrystallization behaviour in MoSi2 in both single phase and multilayers. SiC, in single phase form, remains amorphous up to 900 degrees-1 h anneal, while in multilayers it starts to crystallize at 700 degrees C. Annealing at 900 degrees C for 2 h causes the spheroidization of the layering which results in the formation of a nanocrystalline equiaxed microstructure. Abnormal grain growth is observed after the spheroidization. The crystallization process is directly responsible for the hardness and modulus increase in both single phase and multilayered films. A maximum hardness of 25.5 GPa and a modulus of 382 GPa can be achieved through crystallizing both MoSi2 and SiC layers. Prolonged high temperature exposure causes hardness degradation due to grain growth but the modulus remains almost constant. The layered geometry offers better elastic properties (higher modulus) than the single phase films.",
author = "Harriet Kung and Tom Jervis and Juha-Pekka Hirvonen and John Embury and Terry Mitchell and Michael Nastasi",
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pages = "759--779",
journal = "Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties",
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Structure and mechanical properties of MoSi2-SiC nanolayer composites. / Kung, Harriet; Jervis, Tom; Hirvonen, Juha-Pekka; Embury, John; Mitchell, Terry; Nastasi, Michael.

In: Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties, Vol. 71, No. 4, 1995, p. 759-779.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Structure and mechanical properties of MoSi2-SiC nanolayer composites

AU - Kung, Harriet

AU - Jervis, Tom

AU - Hirvonen, Juha-Pekka

AU - Embury, John

AU - Mitchell, Terry

AU - Nastasi, Michael

PY - 1995

Y1 - 1995

N2 - A systematic study of the structure-mechanical properties relationship is reported for both single phase and nanolayer composites of MoSi2 and SiC. Single phase or alternating layers of MoSi2 and SiC were synthesized by d.c.-magnetron and r.f.-diode sputtering, respectively. Cross-sectional transmission electron microscopy was used to examine several distinct reactions in the specimens when annealed at progressively higher temperatures: crystallization and phase transformation of MoSi2, crystallization of SiC, layer spheroidization, and grain growth. Nanoindentation was employed to characterize the mechanical response of the materials as a function of the structural changes. As-sputtered material exhibits an amorphous structure in both single phase and multilayer forms. Heat treatment induces similar recrystallization behaviour in MoSi2 in both single phase and multilayers. SiC, in single phase form, remains amorphous up to 900 degrees-1 h anneal, while in multilayers it starts to crystallize at 700 degrees C. Annealing at 900 degrees C for 2 h causes the spheroidization of the layering which results in the formation of a nanocrystalline equiaxed microstructure. Abnormal grain growth is observed after the spheroidization. The crystallization process is directly responsible for the hardness and modulus increase in both single phase and multilayered films. A maximum hardness of 25.5 GPa and a modulus of 382 GPa can be achieved through crystallizing both MoSi2 and SiC layers. Prolonged high temperature exposure causes hardness degradation due to grain growth but the modulus remains almost constant. The layered geometry offers better elastic properties (higher modulus) than the single phase films.

AB - A systematic study of the structure-mechanical properties relationship is reported for both single phase and nanolayer composites of MoSi2 and SiC. Single phase or alternating layers of MoSi2 and SiC were synthesized by d.c.-magnetron and r.f.-diode sputtering, respectively. Cross-sectional transmission electron microscopy was used to examine several distinct reactions in the specimens when annealed at progressively higher temperatures: crystallization and phase transformation of MoSi2, crystallization of SiC, layer spheroidization, and grain growth. Nanoindentation was employed to characterize the mechanical response of the materials as a function of the structural changes. As-sputtered material exhibits an amorphous structure in both single phase and multilayer forms. Heat treatment induces similar recrystallization behaviour in MoSi2 in both single phase and multilayers. SiC, in single phase form, remains amorphous up to 900 degrees-1 h anneal, while in multilayers it starts to crystallize at 700 degrees C. Annealing at 900 degrees C for 2 h causes the spheroidization of the layering which results in the formation of a nanocrystalline equiaxed microstructure. Abnormal grain growth is observed after the spheroidization. The crystallization process is directly responsible for the hardness and modulus increase in both single phase and multilayered films. A maximum hardness of 25.5 GPa and a modulus of 382 GPa can be achieved through crystallizing both MoSi2 and SiC layers. Prolonged high temperature exposure causes hardness degradation due to grain growth but the modulus remains almost constant. The layered geometry offers better elastic properties (higher modulus) than the single phase films.

U2 - 10.1080/01418619508236219

DO - 10.1080/01418619508236219

M3 - Article

VL - 71

SP - 759

EP - 779

JO - Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties

JF - Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties

SN - 0141-8610

IS - 4

ER -