| Autor: |
Vyval, I. P., Kavich, I. V., Mikolaichuk, A. G. |
| Zdroj: |
Materials Science; July 1966, Vol. 1 Issue: 4 p312-316, 5p |
| Abstrakt: |
1.The dependence of the TVMT-induced strength of the steels investigated upon the number n of deformation cycles passes through a maximum, which with increase in deformation amplitude is shifted toward lower values of n. The maximum hardness coincides with the maximum UTS. The ductility of specimens given optimum TVMT differs little from that of the control specimens and decreases slightly with increasing n.2.The maximum strength after TVMT is attained following low-temperature (150–200°C) tempering; the time of tempering at these temperatures has no effect upon the resulting increase in strength. The strengthening effect of TVMT is considerably reduced by tempering at 300–400°C and may be completely destroyed by a sufficiently long tempering treatment.3.Varying the TVMT temperature in the 840–900°C interval has no effect upon the increase in the strength of 35Kh steel but causes a slight improvement in ductility.4.Compared with the conventional quench-hardening treatment, TVMT carried out under optimum conditions produces a certain refinement of the martensite grains. Increasing n above its optimum value causes coarsening of the martensite grains and leads ultimately to the appearance of microscopic fatigue cracks in the material.5.The TVMT-induced increase in strength is not dependent upon block size; it is probably associated with an increase in the angle of disorientation of the blocks and with the precipitation of finely-dispersed carbides formed preferentially in the regions of increased dislocation density. |
| Databáze: |
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