Fracture and Fatigue of Refractory Metal Intermetallic Composites

1998 ◽  
Vol 552 ◽  
Author(s):  
William A. Zinsser ◽  
Sergey Solv'yev ◽  
John J. Lewandowski
Keyword(s):  
Fatigue Crack ◽  
Fatigue Behavior ◽  
Growth Characteristics ◽  
Fatigue Threshold ◽  
Metallic Materials ◽  
Threshold Values ◽  
In Situ Composites ◽  
Loading Rates ◽  
Paris Law

The fracture and fatigue crack growth characteristics of niobium silicide/Nb(ss) in-situ composites as well as a variety of Nb alloys were determined over a range of temperatures and loading rates. It is shown that the in-situ composites exhibited nominally rate-independent and temperatureindependent values for the toughness with an average toughness exceeding 24 MPa.m0.5. The fatigue behavior of both the Nb alloys and in-situ composites revealed that both the Paris Law exponents and fatigue threshold values were similar to that exhibited by metallic materials.

Computed Dependence of Rubber'S Fatigue Behavior on Strain Crystallization

2009 ◽  
Vol 82 (1) ◽  
pp. 51-61 ◽  
Author(s):  
W. V. Mars
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Behavior ◽  
Operating Conditions ◽  
Fatigue Threshold ◽  
Crack Growth Behavior ◽  
Fatigue Crack Nucleation ◽  
Nucleation Behavior ◽  
Wide Range

Abstract This work explores the consequences of strain crystallization on rubber's fatigue crack nucleation behavior over an extensive space of operating conditions, including tension and compression loading states, and relaxing and non-relaxing cycles. The study considers, via computation, how the nonlinear elastic stress-strain behavior, the fatigue crack growth characteristics, and the damage accumulation law combine to produce the Haigh diagram and the Cadwell diagram. Four hypothetical materials are studied, which differ in their crystallization and associated fatigue crack growth behavior. The calculations demonstrate that a relatively simple idealization can credibly predict the unique shape and sensitivities of observed fatigue behavior over a wide range of conditions. They also clarify how features of the Haigh and Cadwell diagrams are linked to the occurrence of crystallization and to parameters such as the power-law slope and the fatigue threshold.

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