Formation of disordered structures in Cr-Fe alloy by mechanical milling

Abstract

Mechanical milling was performed on the alloy CrnFeB. X-ray diFSraction and Mlissbauer spectmscopy were used IO follow the progress of the shuctural variation. The experimental results can be interpreted by assuming that the milled powden are composed of a small amount of crystalline component and two disordered components: one with a &om densely packed shucLure and the 0 t h with a random lwsely packed structure. Moreover, differential scanning d o r i m e y was used to obIain the crystallization temperature. A mechanism was proposed la describe the formation of Ihe disordered sttuctwes as well as Ihe structural stability in this alloy.

Phase transformations of σ-FeCr induced by ball milling

“…Thus, we attribute the central peak of the Mössbauer spectra to an amorphous phase with an average isomer shift of −0.08(2) mm/s in agreement with the results of Xia et al [13].…”

“…Further, a contamination by steel coming from milling tools would contribute to a Fe-enrichment of the milled powders and thus to an increase of the measured magnetic moment. At least two assumptions can be put forward to explain a magnetisation decrease: (a) the formation of an amorphous phase [12,13], which is non-magnetic in the studied concentration range and is possibly favoured by the presence of oxygen in ball-milled alloys [14]; (b) a phase separation with a significant amplitude which is difficult to evidence by X-ray diffraction in such alloys.…”

Debye temperature of nanocrystalline Fe–Cr alloys obtained by mechanical alloying

“…The relative spectral areas of M and P sub spectra are marked by A, and the average isomer shift by <IS> (relative to the -Fe). It is observed that the shape and the range of QS-values seen in the presently determined QSD histograms agree well with those previously reported [15,16,21] for amorphous Fe-Cr alloys. From the data displayed in Table 2 one can see that the abundances of the M-phases agree fairly well with the intensities of the narrow diffraction peak, while those of the P-phases are in line with the intensities of the broad XRD peak.…”

“…For Fe-Cr alloys, several studies conducted by ball milling showed their amorphization e.g. [13][14][15][16][17][18][19][20][21]. In particular, in equiatomic or near-equiatomic FeCr alloys milled in vacuum or argon atmosphere, this effect was observed both in alpha and sigma phases, e.g.…”

Mechanically induced phase transformations of the sigma phase of nanograined and of coarse-grained near-equiatomic FeCr alloys

“…Indeed, iron and near-equiatomic Fe-Cr alloys were shown to be sensitive to the presence of gases when ground in high-energy ball-mills [20][21][22][23][24][25][26][27][28][29]. Rawers et al [20][21][22] compared the microstructures of ␣-Fe ground in argon and in nitrogen in a Szegvari type attrition mill.…”