ISSN:
0933-5137
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
By means of the inclusion of a dispersed phase with low Young's modulus, the generally low thermal stress resistance of brittle materials for high-temperature structures can be improved significantly. An analysis of this improvement on the basis of continuum and micromechanical theory is presented in this paper.The low-E phase is shown to cause a significant decrease in Young's modulus, with a negligible effect in the coefficient of thermal expansion. The relative change in thermal conductivity is a function of the thermal conductivity of the dispersed phase.The tensile fracture stress is reduced significantly, primarily due to the mismatch in elastic properties, with smaller effects due to the mismatches in the coefficient of thermal expansion and thermal conductivity.The relative changes in Young's modulus and tensile fracture stress are such as to result in an increase in the strain-at-fracture and a simultaneous decrease in the elastic energy at fracture, the driving force for catastrophic crack propagation. The accompanying increase in fracture energy also contributes to the improvement of thermal shock resistance. By changing the size of the low-E inclusion, tradeoffs can be made between strain-at-fracture and elastic energy at fracture.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mawe.19800110305
