Author: Christopher Joseph GilbertPublisher:
ISBN:
Category :
Languages : en
Pages : 618
Book Description
Ambient and Elevated Temperature Fracture and Cyclic-fatigue Properties of in Situ Toughened Ceramics
Author: Christopher Joseph GilbertPublisher:
ISBN:
Category :
Languages : en
Pages : 618
Book Description
Ambient and Elevated Temperature Fracture and Cyclic-fatigue Properties in a Series of Al-containing Silicon Carbides
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 86
Book Description
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. In addition an investigation of fracture resistance in non-transforming ceramics toughened by grain bridging mechanism is presented using linear elastic fracture mechanics (LEFM). Linear superposition theorems are used for the superposition of crack opening displacements, as well as stress intensity factors, resulting from the external tractions and the internal compressive bridging stresses. Specifically weight functions are used to relate the CODs, stress intensity factors, and tractions and the bridging stress. Expressions are derived for apparent material resistance, the bridging resistance and the intrinsic toughness, and an experimental procedure is proposed by which these predictions can be verified.
Ambient and Elevated Temperature Fracture and Cyclic-fatigue Properties of Boron-modified Molybdenum Silicides
Author: Heeman ChoeAmbient and Elevated Temperature Fracture and Cyclic-fatigue Properties in a Series of Al-containing Silicon Carbide Ceramics
Author: Rong Yuan (M.S.)Ambient and Elevated Temperature Fracture and Cyclic-fatigue Properties in a Series of A1-containing Silicon Carbide Ceramics
Author: Jung YüanAmbient to High-temperature Fracture Toughness and Cyclic Fatigue Behavior in Al-containing Silicon Carbide Ceramics
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 5
Book Description
A series of in situ toughened, A1, B and C containing, silicon carbide ceramics (ABC-SiC) has been examined with A1 contents varying from 3 to 7 wt percent. With increasing A1 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.
Handbook of Advanced Ceramics
Author: Tatsuki OhjiPublisher: Elsevier Inc. Chapters
ISBN: 0128057343
Category : Technology & Engineering
Languages : en
Pages : 65
Book Description
Fracture Mechanics of Ceramics
Author: R.C. BradtPublisher: Springer Science & Business Media
ISBN: 1461558530
Category : Technology & Engineering
Languages : en
Pages : 591
Book Description
Second part of the proceedings of the Sixth International Symposium held in Karlsruhe, Germany, July 18-20, 1995.
Fatigue of Ceramics at Elevated Temperatures
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 12
Book Description
The high-temperature mechanical properties of an in-situ toughened silicon carbide have been examined at temperatures from ambient to 1300C with the objective of optimizing structural performance.
Author: Alexander Ziegler