Spherical‐Impact Damage and Strength Degradation in Silicon Nitrides for Automobile Turbocharger Rotors

Akimune, Yoshio; Katano, Yasushi; Matoba, Kazuo

doi:10.1111/j.1151-2916.1989.tb07664.x

Cited by 52 publications

(19 citation statements)

References 25 publications

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“…T he model, despite several assumptions, was in good agreement with experimental data determin ed for glass impacted by steel or tungsten ca rbid e spherical projectiles [I]. The resulting strength degradati on as a function of impact velocity is expressed as follows [1]: (4) where <1> is a con tant and K lc is fracture tough ness of target material. Equation (4) ca n also be expressed in tenns of impact kinetic energy, U r mV2/2 wi th m being the projectil e mass, to yield The post-impact stTength (log OJ) data shown in Figure 4 were plotted as a function of impact ki netic energy (log UK) in Figure II based on Eq .…”

Section: Analytical Considerations Of Strength De Gradationmentioning

confidence: 52%

“…Tn cases of impacts with hard projectiles vs. hard ta rget materials (such as cerami c balls vs. cerami c target materials), it has been shown that agreement between the calcul ated contact area (radius) and the upper size (radius) of a cone was reasonabl e [4]. T he contact area can be estimated based on the Hertzian contact theory together with the princi ple of co nservation of impact energy as follows [1, 4,5,8]:…”

Section: Contact Ar Eas/impressionsmentioning

confidence: 99%

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Foreign Object Damage of Two Gas-Turbine Grade Silicon Nitrides in a Thin Disk Configuration

Choi

Pereira

Janosik

et al. 2003

Volume 1: Turbo Expo 2003

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A BSTRACTForeign object damage (FOD) behavior of two commercial gasturbine grade silicon nitrides, AS800 and SN282, wa determined at ambient temperature through post-impact st rength testing for thin disks impacted by steel-ball projectiles with a diameter of I.S9 mm in a velocity range from 115 to 440 m/s. AS800 silicon nitrid e ex hibited a greater FOD resistance than SN282, primarily due to its greater va lue of fracture toughness (Kid. The criti cal impact velocity in which th e correspo nd ing post-impact strength yielded the lowest va lue was V c ",,440 and 300 m/s fo r AS800 and SN282, respec ti ve ly. A unique lower-trength regime was typified fo r both silicon nitrides depending on impac t velocity, attributed to signi ficant radial cracking. The damages generated by projectile impact were typically in the fonns of ring, radial, and cone cracks with their severity and combinati on being dependent on impact velocity.U nl ike thick (3 mm) flexu re bar specimens used in the previous studies, th in (2 mm) disk target specimens exhibited a unique backside radial cracking occu rring on the reverse side just beneath the impact si tes a t and above impact veloci ty of 160 and 220 ml s fo r SN282 and AS800, respectively. INTRODUCTIONCerami cs, because of thei r brittle natu re, are susceptible to locali zed surface damage and/or cracking when subjected to impact by foreign objects. It is also true that cerami c components may fail structu rally even by soft particles when the kinetic energy of impacting objects exceeds certai n limi ts. The latter case has been often found in aerospace engi nes in which combus tion products, metallic parti cles or small fo reign objects cause severe damage to bl ade/vane components, resulting in serious s tructural problems. Therefore, foreign obj ec t damage (FOD) associated with particle impact needs to be considered when ceramic materials are designed fo r structu ral app licatio ns. In view of this importance, a considerable amou nt of work on impact damage of brittle materials by sharp particles as we ll as by "blunt" particles or by plates has been accumula ted both ex perimentally and

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Section: Analytical Considerations Of Strength De Gradationmentioning

confidence: 52%

Section: Contact Ar Eas/impressionsmentioning

confidence: 99%

Foreign Object Damage of Two Gas-Turbine Grade Silicon Nitrides in a Thin Disk Configuration

Choi

Pereira

Janosik

et al. 2003

Volume 1: Turbo Expo 2003

View full text Add to dashboard Cite

show abstract

“…Considerable effort has been expended develop methods for evaluating silicon carbide (SiC) or erosion-related ceramic and ceramic composite materials used in engineering components in such applications as gas turbine parts, sealing bearings, and burner parts [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58]. These applications may involve solid-particle impact and erosive wear, and it is therefore necessary to have some knowledge of behaviours and mechanisms before the materials can be used with confidence.…”

Section: Introductionmentioning

confidence: 99%

Erosive Wear Mechanism of New SiC/SiC Composites by Solid Particles

Suh

Hinoki

2010

Tribol Lett

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A solid-particle erosive wear test by impinging silicon carbide (SiC) powders was carried out at room temperature over a range of median particle sizes of 425-600 lm, speed of 100 m/s and impact angle of 90°a nd assessed by wear measurements and scanning electron microscopy. Erosive wear behaviour was examined on newly fabricated nano-powder infiltration and transient eutectoid (NITE) SiC/SiC composites and two commercial composites by the chemical vapour infiltration (CVI) and NITE fabrication route. Microstructural observation was performed to examine the correlation between erosive wear behaviours and fabrication impurities. Conspicuous defects were observed in the prototype materials as the forms of porosity, fibre deformation, residual oxide, pyrolytic carbon (PyC) deformation, PyC cleavage, among others. Erosive wear behaviour was rather serious in the prototype of fabricated composites, which employ pre-SiC fibre and phenolic resin. Two dominant erosive wear mechanisms were observed: delamination of constituents, mainly caused by erosive crack propagation, and fragmentation and detachment of constituents, which usually resulted from erosive impact. A unit size of delamination was the most decisive factor affecting wear volume. The bonding strength of each constituent was mostly affected by various forms of porosities. Therefore, the fundamental cause and subsequent results must be carefully elucidated. The correlation of microstructural defect and wear behaviour was investigated with the aim of reducing dominant wear by improving fabrication conditions. The final product of the cost-effective composite had a 2.5-fold higher resistance than the commercial CVI composite. Consequently, by controlling fabrication impurities, we have been successful in developing and improving a new fabrication technique; consequently, the known defects are rarely observed in final product. A schematic wear model of erosive wear mechanisms is proposed for the newly fabricated SiC/SiC composites under particle erosion.

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“…In particular, to the authors' knowledge, few studies have been performed on the impact behaviour of monolithic fine-grained structural ceramics and most of these dealt with non-oxide materials. [7][8][9][10][11][12][13][14][15][16] The kind and extension of damage mechanisms that take place during the impact determine the impact behaviour. 3,17 However, the damage accumulation in the materials after the impact can lead to a severe loss in the strength and, thus, in the structural integrity necessary for the required applications.…”

Section: Introductionmentioning

confidence: 99%

Reduced strength degradation of alumina–aluminium titanate composite subjected to low-velocity impact loading

Bueno¹,

Micele²,

Baudin³

et al. 2008

Journal of the European Ceramic Society

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Spherical‐Impact Damage and Strength Degradation in Silicon Nitrides for Automobile Turbocharger Rotors

Cited by 52 publications

References 25 publications

Foreign Object Damage of Two Gas-Turbine Grade Silicon Nitrides in a Thin Disk Configuration

Foreign Object Damage of Two Gas-Turbine Grade Silicon Nitrides in a Thin Disk Configuration

Erosive Wear Mechanism of New SiC/SiC Composites by Solid Particles

Reduced strength degradation of alumina–aluminium titanate composite subjected to low-velocity impact loading

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