ISSN:
1573-9066
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Conclusions An investigation was carried out into the effect of thermal cycling on the structural state of polycrystals based on the high-density boron nitride modifications. It is shown that a two-phase material is characterized by a high level of macro- and microstresses, which control its brittle rupture behavior and mechanical properties. In particular, microcracking processes initiated by internal stresses after the application of external load promote stress relaxation at the tip of a propagating macrocrack, thereby imparting high fracture toughness (Kc ∼16–18 MN/m3/2) to the material. During heat treatment (performed in this work at T ⩾ 800°C) internal stress relaxation takes place, which is accompanied by a fall in fracture toughness to the level characteristic of unstressed single-phase sintering (Kc ∼10–14 MN/m3/2) and changes in hardness and rupturing stress.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00791909
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