A diffraction study of γ-Mn-Cu alloys

摘要: A study of some Mn-Cu alloys in the gamma -phase has been made using neutron and X-ray diffraction at low temperatures. For manganese-rich variation magnetic moment with composition was measured critical concentration for antiferromagnetic ordering deduced to be xc=0.72. measurement unit cell dimensions 4.2K showed order accompanied by tetragonal distortion c/a 1 orthorhombic), observed other solutes manganese, were not detected these measurements on -Mn-Cu alloys. Using results a phase diagram drawn which could compared those diagrams obtained calculation. The performance molecular field model martensitic transformation also investigated close concentration. found less successful here than when applied antiferromagnetism is well established. diffuse scattering from two Mn0.65Cu0.35 Mn0.60Cu0.40 analysed give information spatial short-range specimens This (SRO) appears based type 3 structure, rather exists as long-range ordered state Finally an analysis nuclear specimen yielded values atomic SRO parameters similar derived elsewhere, suggested that only weakly developed specimens.