| Autor: |
Firstov, S., Podrezov, Yu., Zherdin, A., Shtyka, L., Pioro, É., Golovkova, M., Pioro, N. |
| Zdroj: |
Soviet Powder Metallurgy & Metal Ceramics; 1988, Vol. 27 Issue 3, p212-215, 4p |
| Abstrakt: |
The presence of pores in the material leads to the redistribution of stresses in the material and to localization of strains in small volumes between the pores. The susceptibility to ductile failure increases with increasing porosity. At −196°C, the failure mechanism of the porous materials based on iron changes from ductile to brittle (cleavage) with decreasing porosity. The dependence of cracking resistance on the porosity of these materials is nonmonotonic and the maximum cracking resistance is recorded at porosity values at which the failure mechanism changes. The nonmonotonic nature of cracking resistance reflects the high sensitivity of this characteristic to the change of the stress state in the material. The change of the stress state in the ductile-brittle transition temperature range can be described by the condition σ = σ. In the porous materials examined this condition is valid because of the specific form of the σ-Θ and σ-Θ dependences. The model of the ductile-brittle transition proposed in this work can be used to determine the analogy between the cold brittleness temperature T and the critical value of porosity σ corresponding to the point of intersection of the σ-Θ and σ-Θ curves for the porous materials. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
