ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Unbekannt

Investigation of the fracture mechanics of boride composites (1972)

Kaufman, L. A.

In: CASI

zur Merkliste hinzufügen auf der Merkliste

Details

Publikationsdatum: 2019-06-27

Beschreibung: Processing studies designed to produce boride composites with metal additives to lower fabrication temperatures and increase the impact strength are reported. Hot pressing experiments were performed with ZrB2 and Fe, Ti, and Zr employed singly as additives. Data for the characterization, impact tests, slow bend tests, and fracture strength are presented.

Schlagwort(e): MATERIALS, NONMETALLIC

Materialart: NASA-CR-126246 , QR-5

Format: application/pdf

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

NASA TECHNICAL REPORTS

S·F·X

Überblick

2

Unbekannt

Investigation of the fracture mechanics of boride composites (1971)

Nesor, H. ; Clougherty, E. V. ; Kaufman, L.

In: CASI

zur Merkliste hinzufügen auf der Merkliste

Details

Publikationsdatum: 2019-06-27

Beschreibung: Fracture energies of WC-6Co, Boride 5 (ZrB2+SiC), Boride 8(ZrB2+SiC+C) and Boride 8-M2(ZrB2+SiC+C) were measured by slow bend and impact tests of notched charpy bars. Cobalt bonded tungsten carbide exhibited impact energies of 0.76 ft-lb or 73.9 in-lb/square inch. Boride 5 and the Boride 8 exhibit impact energies one third and one quarter of that observed for WC-6Co comparing favorably with measurements for SiC and Si3N4. Slow bend-notched bar-fracture energies for WC-6Co were near 2.6 in-lb/square inch or 1/20 the impact energies. Slow bend energies for Boride 8-M2, Boride 8 and Boride 5 were 58%, 42% and 25% of the value observed for WC-6Co. Fractograph showed differences for WC-6Co where slow bend testing resulted in smooth transgranular cleavage while samples broken by impact exhibited intergranular failures. By contrast the boride fractures showed no distinction based on testing method. Fabrication studies were conducted to effect alteration of the boride composites by alloying and introduction of graphite cloth.

Schlagwort(e): MATERIALS, NONMETALLIC

Materialart: NASA-CR-124732

Format: application/pdf

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

NASA TECHNICAL REPORTS

S·F·X

Überblick

3

Unbekannt

Investigation of the fracture mechanics of boride composites (1972)

Kaufman, L. ; Clougherty, E. V. ; Pober, R. L.

In: CASI

zur Merkliste hinzufügen auf der Merkliste

Details

Publikationsdatum: 2019-06-27

Beschreibung: Significant results were obtained in fabrication studies of the role of metallic additives of Zr, Ti, Ni, Fe and Cr on the densification of ZrB2. All elemental additions lower the processing temperatures required to effect full densification of ZrB2. Each addition effects enhanced densification by a clearly distinguishable and different mechanism and the resulting fabricated materials are different. A significant improvement in strength and fracture toughness was obtained for the ZrB2/Ti composition. Mechanical characterization studies for the ZrB2/SiC/C composites and the new ZrB2/Metal materials produced data relevant to the effect of impacting load on measured impact energies, a specimen configuration for which controlled fracture could occur in a suitably hard testing apparatus, and fracture strength data. Controlled fracture--indicative of measurable fracture toughness--was obtained for the ZrB2-SiC-C composite, and a ZrB2/Ti composite fabricated from ZrB2 with an addition of 30 weight per cent Ti. The increased strength and toughness of the ZrB2/Ti composite is consistent with the presence of a significantly large amount of a fine grained acicular phase formed by reaction of Ti with ZrB2 during processing.

Schlagwort(e): MATERIALS, NONMETALLIC

Materialart: NASA-CR-131877

Format: application/pdf

Permalink