ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The fracture toughness of a high yield strength grade of hot-pressed beryllium block was determined at room temperature and 300° C. Fatigue cracks were generated in doublecantilever beam specimens by a reversed loading method. Room temperature fracture toughness values from specimens with electric discharge machined notches fell within the scatter band of values from specimens with fatigued precracks. Load—displacement records generated from test on specimens with machined notches exhibited the expected linearity. However, the records were nonlinear from tests on specimens with long cracks formed by repeated propagation and arrest. Evidence points to a crack-closure phenomenon rather than plasticity as the source of the nonlinearity. The fracture toughness data show that specimen orientation or test temperature have little effect. By contrast, reported ductility values for this material are very sensitive to both these variables. The mean value of the fracture toughness ranged from 9.0 MPa m1/2 (8.1 ksi in. 1/2) at 23° C to 10.8 MPa m1/2 (9.7 ksi in. 1/2) at 300° C. These values are among the lowest ever reported for beryllium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00542802
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