Ion Beam Mixing of Ceramic Alloys - Preparation Andmechanical Properties

Lewis, Morgan; McHargue, C.J.

doi:10.1557/proc-7-85

Cited by 1 publication

(4 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…21): AT, is nearly unaffected by the number of quenches, as is the retained strength at AT >> AT,. The only notable result is a more rapid strength degradation with increasing AT and re- ZrOz [73]: Festigkeit (RT) als Funktion der Differenz der Abschrecktemperatur (Probenquerschnitt: 3,2 x 3,2 mm). A1203-PSZ (25 vol.% Zr02) (Fig.…”

Section: A1203-mo-fibresmentioning

confidence: 99%

“…24. Influence of multiple quenching in water (22 "C) on the thermal stress resistance of a AI,O,-BN composite [73]: strength (RT) as a function of quenching temperature difference (specimen dimensions 3.2 X 3.2 mm). Abb.…”

mentioning

confidence: 99%

“…24. Einflul3 einer mehrfachen Abschreckung in Wasser (22 "C) auf das Thermoschockverhalten eines A1,03-BN-Verbundwerkstoffs [73]: Festigkeit (RT) als Funktion der Differenz der Abschrecktemperatur (Probenquerschnitt 3,2 X 3,2 mm). Though at the present time the decisive mechanism for the thermal shock behaviour of both types of fracture toughened materials under multiple quenches cannot be given (possible mechanisms are: increase in flaw density, change in crack length, crack-microstructure interaction, reduction of possible compressive stresses in the surface), some conclusions may be drawn: The positive effect achieved by materials development can be partly reduced by multiple quenches.…”

mentioning

confidence: 99%

“…Though at the present time the decisive mechanism for the thermal shock behaviour of both types of fracture toughened materials under multiple quenches cannot be given (possible mechanisms are: increase in flaw density, change in crack length, crack-microstructure interaction, reduction of possible compressive stresses in the surface), some conclusions may be drawn: The positive effect achieved by materials development can be partly reduced by multiple quenches. Significant effects after multiple quenching have been observed in those materials known to exhibit substantial microcracking [73]. This behaviour is to be taken into account when using such materials for applications involving repeated thermal shock.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Microstructural aspects of Thermal Stress Resistance of high‐strength engineering ceramics. Part III: Improvement of thermal stress resistance of high‐strength engineering ceramics

Ziegler¹

1985

Materialwissenschaft Werkst

View full text Add to dashboard Cite

The main objectives of parts I and I1 of this paper were: basic criteria for the improvement of thermal shock resistance of engineering ceramics; data about the thermal stress resistance of high-strength engineering ceramics (thermal shock and thermal cycling); and the influence of microstructure on thermal shock resistance to fracture initiation, including the influence of various microstructural variables on the mechanical and thermal properties which mainly control the thermal shock resistance to fracture initiation. In part I11 of this paper the possibility to improve the thermal shock resistance to fracture initiation by microstructural optimization is demonstrated. This includes a description of the different steps of the improving procedure. Moreover, the improvement of thermal stress resistance by developing advanced composite materials based on theoretical considerations of improving some important properties by microstructural design is outlined. Here the results of previous investigations and of recent developments are summarized. Improvement of Thermal Stress ResistanceDue to theoretical studies, in particular of 0. P. H . Hasselman, the requirements for high thermal stress resistance of engineering ceramics are known (see chapter 2):-If initiation of thermal stress fracture must be avoided, materials are necessary which have high values of tensile strength, thermal conductivity and diffusivity and low values of coefficient of thermal expansion, Young's modulus of elasticity, and Poisson's ratio;-if fracture initiation cannot be avoided, the development of lower strength materials, implying large flaw size and/or high densities of flaws, will minimize structural degradation;-by designing microstructures which increase surface fracture energy andlor decrease elastic moduli an increase in thermal stability can be attained. For many applications the question is how these requirements can be realized. There are some possibilities:-to select materials with a combination of properties so that for the required thermal stress conditions and for a certain failure mechanism (unstable or stable crack propagation) these materials have a maximum thermal stress resistance. In this scope it should be confirmed that besides fracture strength and thermal conductivity in particular low values of the coefficient of thermal expansion, but also low values of Young's modulus of elasticity result in an improvement of thermal shock resistance;-to create compressive stresses in the region of the material where the failure originates which opposes the tensile stresses. Prestressing by quenching and coating was found to improve the thermal stress resistance of some materials -to optimize the microstructure for the selected material group with respect to the required heat transfer condition;-to develop advanced materials based on the theoretical considerations to increase surface fracture energy and crack density. Two development lines, the improvement of thermal stress resistance by microstructural optimization, and by incorpo...

show abstract

Section: A1203-mo-fibresmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations