Effect of orientation and temperature on deformation behavior of Fe-0.1 wt.%P and Fe-0.1 wt.%P-0.16 wt.%Ti single crystals

Abstract

The orientation dependence of the deformation behavior and the strain rate sensitivity of the flow stress of ZrH 2-purified Fe-0.1P and titanium-gettered Fe-0.1P-0.16Ti single crystals (where the alloy compositions are given in weight per cent) were investigated at temperatures between 77 and 373 K. Comparisons were made between deformation behaviors of ZrH 2-purified Fe-0.1P and iron single crystals and between the deformation behaviors of Fe-0.1P-0.16Ti and Fe-0.16Ti single crystals, as well as between the deformation behaviors of phosphorus-containing single crystals and the corresponding polycrystalline alloys. The results showed that there was np apparent orientation dependence of the critical resolved shear stress or the thermal activation parameters in the Fe-0.1P-0.16Ti crystals. This behavior, like that in the Fe-0.16Ti crystals, appeared to be in qualitative agreement with impurity models of the low temperature deformation behavior in b.c.c. metals which predict such behavior because of the absence of mobile interstitial atoms in these crystals. The absence of any apparent orientation dependence of the critical resolved shear stress or the thermal activation parameters in the Fe-0.1P crystals was in sharp contrast with the behavior observed in the iron coystals, and it appeared that orientation-dependent solid solution softening in the Fe-0.1P crystals was the cause of this difference in behaviour Both solid solution hardenin andd solid solution softening in the phosphorus-containing crystals could be explained in terms of elastic interactions theween the phosphorus atoms and screw dislocations as a result of the size and modulus differences between the phosphorus and iron atoms. The magnitudes of the solid solution hardening and the solid solution softening were similar in the phosphorus-containing crystals and the corresponding polycrystalline alloys.