Microstructure development in hot-pressed silicon carbide: effects of aluminum, boron, and carbon additives

Zhang, Xiao Feng; Yang, Qing; Jonghe, Lutgard C. De

doi:10.1016/s1359-6454(03)00209-x

Cited by 57 publications

(38 citation statements)

References 48 publications

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“…Chen et al [9][10][11] found that in addition to conferring good high-temperature creep and fatigue resistance, such heat treatments led to a ~20% increase in the room-temperature fracture toughness and fatigue-crack growth resistance (with no change in mechanism), compared to that in the as-hot-pressed material. However, an alternative approach is via microstructure modification through compositional changes, specifically by varying the aluminum content [15]. To date, several ABC-SiC materials have been processed with aluminum contents between 3 and 7 wt.%, where the changing Al additions resulted in significantly altered microstructures [7][8][9][10][11]15].…”

Section: Introductionmentioning

confidence: 99%

“…However, an alternative approach is via microstructure modification through compositional changes, specifically by varying the aluminum content [15]. To date, several ABC-SiC materials have been processed with aluminum contents between 3 and 7 wt.%, where the changing Al additions resulted in significantly altered microstructures [7][8][9][10][11]15]. Whereas the 3 wt.% material (3ABC) develops a microstructure of relatively uniform elongated grains with amorphous grain-boundary films (as noted above), a bimodal distribution of both elongated and equiaxed grains with partially crystallized grain-boundary films is seen in the 5ABC material, compared to principally equiaxed grains with only a few elongated (needle-like) grains, all with fully crystallized grain boundaries, in the 7ABC-SiC.…”

Section: Introductionmentioning

confidence: 99%

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Ambient to high-temperature fracture toughness and cyclic fatigue behavior in Al-containing silicon carbide ceramics

et al. 2003

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Abstract-A series of in situ toughened, Al, B and C containing, silicon carbide ceramics (ABC-SiC) has been examined with Al contents varying from 3 to 7 wt%. With increasing Al additions, the grain morphology in the as-processed microstructures varied from elongated to bimodal to equiaxed, with a change in the nature of the grain-boundary film from amorphous to partially crystalline to fully crystalline. Fracture toughness and cyclic fatigue tests on these microstructures revealed that although the 7 wt.% Al containing material (7ABC) was extremely brittle, the 3 and particularly 5 wt.% Al materials (3ABC and 5ABC, respectively) displayed excellent crack-growth resistance at both ambient (25°C) and elevated (1300°C) temperatures. Indeed, no evidence of creep damage, in the form of grain-boundary cavitation, was seen at temperatures at 1300°C or below. The enhanced toughness of the higher Al-containing materials was associated with extensive crack bridging from both interlocking grains (in 3ABC) and uncracked ligaments (in 5ABC); in contrast, the 7ABC SiC showed no such bridging, concomitant with a marked reduction in the volume fraction of elongated grains. Mechanistically, cyclic fatigue-crack growth in 3ABC and 5ABC SiC involved the progressive degradation of such bridging ligaments in the crack wake, with the difference in the degree of elastic vs. frictional bridging affecting the slope, i.e., Paris law exponent, of the crack-growth curve.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ambient to high-temperature fracture toughness and cyclic fatigue behavior in Al-containing silicon carbide ceramics

et al. 2003

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“…The joining temperature is chosen for the crystallizing of grain-boundary phase. 9) For comparison, another tape-like joining material starting from ¡-SiC powder was also used for the joining of SiC. As a result, we obtain nearly full dense SiC joints.…”

Section: Mechanical Properties Of Sic Jointsmentioning

confidence: 99%

“…7) It was demonstrated that SiC ceramics can be densified at temperatures lower than 1900°C with AlBC additives. The sintered SiC shows improved ambient-temperature fracture toughness and strength, 8), 9) and stable high-temperature toughness/creep behavior at temperatures up to 1300°C. 10) Effect of the forms of sintering additives in AlBC system, e.g.…”

Section: Introductionmentioning

confidence: 99%

Effect of composition and joining parameters on microstructure and mechanical properties of silicon carbide joints

Tian

Kita

Kondo

et al. 2010

J. Ceram. Soc. Japan

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Powder-and tape-like joining materials composed of SiC with AlBC (ABC) or AlB 4 CC (ABCC) sintering additives were used for the joining of SiC. The effect of interlayer composition, joining temperature and particle size of SiC on the microstructure and mechanical properties of SiC joints was studied. The results indicated that the tape-like adhesive introduces denser microstructure of interlayer relative to the powder-like one under the same conditions. It was demonstrated that using fine starting SiC powder instead of coarse one enhances the densification process of SiC joints. As joined at 1650°C, the microstructure of interlayer is improved gradually with the increasing Al content from 1 to 6 wt % in composition while slightly affected by the forms of additives, i.e. ABCC additive having the equal action to ABC one on the densification of joints. At higher joining temperature of 1750°C, the microstructure of interlayer containing 3 wt % Al almost does not change while that containing 6 wt % degrades. SiC joints with strength higher than 344 MPa have been produced by using optimized joining variables, where the fracture of bonded SiC generally occurs within the SiC substrate.

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“…Silicon carbide (SiC) is a brittle material with hardness of 22-35 GPa and fracture toughness of 2.96-5.8 MPa·m 1/2 [12,13]; SiC finds applications in the areas of protective system, space mirror, and abrasives [14][15][16]. β-SiAlON is relatively less brittle than α-SiC, with hardness of 14-17 GPa and fracture toughness of 6.5-7.88 MPa·m 1/2 [17,18]; β-SiAlON is one of the promising materials for cutting tools, turbine vanes and blades, and turbocharger rotors [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Load-dependent indentation behavior of β-SiAlON and α-silicon carbide

2013

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A comparative study was carried out on the load-dependent indentation behavior with respect to hardness and induced cracks of β-SiAlON and α-silicon carbide ceramics. It is observed that silicon carbide (SiC) exhibits lower transition load, early cracking and severely crushed indentation sites, whereas β-SiAlON shows higher transition load and damage-free indentation zone even at the maximum applied load (294.19 N). Crack density is higher for α-SiC with comparison to β-SiAlON at each load. SiC exhibits both main and secondary radial types of cracking from low indentation load (0.98 N). Cracks are often associated with branching at higher load (> 9.80 N) for α-SiC. β-SiAlON exhibits cracks which are mainly radial types initiated at 4.90 N load. These opposing behaviors of β-SiAlON and α-SiC are attributed to their difference in hardness, toughness, and brittleness index. Higher brittleness of α-SiC results in early and severe cracking around its indentations. β-SiAlON shows less cracking due to its lower brittleness and higher toughness. The increased size of indentation-induced cracks of α-SiC is higher than that of β-SiAlON due to the rapid crack propagation in α-SiC with transgranular fracture behavior.

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Microstructure development in hot-pressed silicon carbide: effects of aluminum, boron, and carbon additives

Cited by 57 publications

References 48 publications

Ambient to high-temperature fracture toughness and cyclic fatigue behavior in Al-containing silicon carbide ceramics

Ambient to high-temperature fracture toughness and cyclic fatigue behavior in Al-containing silicon carbide ceramics

Effect of composition and joining parameters on microstructure and mechanical properties of silicon carbide joints

Load-dependent indentation behavior of β-SiAlON and α-silicon carbide

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