鋼の焼もどし過程における弾性定数ならびに塑性変形挙動のＸ線回折による研究

Abstract

It is well known that X-ray diffraction is advantageous when applied to metalic materials; it is very sensitive to changes in the crystalline structure.In this paper, X-ray diffraction technique which is very important in studies on mechanical behavior of materials, is applied to the relations between the elastic, plastic deformation behavior and submacro- or micro-structure of tempered steels. Ni-Cr-Mo steel (SNCM8) and 0.16%C steel (S15C) are used in this experiment. The main results obtained are as follows.(1) X-ray elastic constants S2/2 and S1 of (211), (200) diffraction planes are decreased with tempering temperature (250°-350°C), but that of (220) diffraction plane does not change over tested tempering temperature.(2) Half value breadth of X-ray diffraction profile is changed by plastic deformation. At tempering temperature below 200°C, half value breadth of (110), (220), (200) and (211) diffraction planes decrease with less than 1% deformation. With over 2% plastic deformation, the half value breadth essentially remains constant. Its manner is the same as for martensite. On the other hand, at tempering temperature above 400°C, half value breadth of (110), (220), (200) and (211) diffraction planes increase with plastic deformation. Its manner is the same as for annealed metals. Between 250°C and 350°C of tempering temperature, however its behavior depends on the diffraction plane. Half value breadth of (200), (211) diffraction planes change in martensitic manner, but that of (110), (220) diffraction planes in annealed manner.