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Altogether 19 alloys of an Al-Mn-Fe system with compositions near to the Taylor phase and/or the decagonal quasicrystal were characterised by the x-ray diffraction and the energy-dispersive x-ray spectroscopy coupled with the scanning electron microscopy, after annealing at 1000 °C for 330 h. The obtained experimental results were used to propose a partial isothermal section at 1000 °C of the Al-Mn-Fe phase diagram. The ternary T-phase area of an untypical saddle shape was found to touch the Al-Mn binary one. The γ-phase was found to be stable between 2 and 30 at.% of Fe at 1000 °C and boundaries between γ- and γ-areas are expected to be located very close to the Al-Mn binary. [ABSTRACT FROM AUTHOR]

Partial isothermal sections of the Al-Co-Cu phase diagram at 800, 1020, and 1050 °C were proposed based on both literature data and own experimental results. By means of x-ray diffraction, electron backscattered diffraction, electron diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, and energy dispersive x-ray spectroscopy altogether five phases (AlCo, m-AlCo, D, B2, and rapidly solidified liquid) were identified in a number of investigated alloys falling within compositional ranges AlCoCu. The single-phase area corresponding in the isothermal sections to the decagonal quasicrystalline phase (D) was found to reduce in size, and to shift to lower Cu and higher Al bulk contents, both with increasing temperature. The single-phase m and AlCo areas showed only small temperature-dependent changes in size and location. Moreover, an increase in temperature caused both a slow decrease of the copper solubility in B2 and an increase of the liquid stability. [ABSTRACT FROM AUTHOR]

Abstract Recently, the Ga-based ternary alloys have gained interest for the possibility of finding new quasicrystals. Inspired by the previously reported decagonal and icosahedral quasicrystals identified in the Ga 50 Co 25 Cu 25 alloy at 830 °C, the phase equilibria of 27 alloys of various composition were investigated in this work. Based on the obtained results, an isothermal section of the Ga-Co-Cu phase diagram at 830 °C was proposed. However, neither decagonal nor icosahedral quasicrystals were found to be stable at 830 °C, but instead of that, a superalloy-like structure was found in the Ga 35 Co 25 Cu 40 alloy consisting of β-GaCo and β-GaCu/ζ-GaCu. Graphical abstract Image 1 Highlights • Isothermal section of the Ga-Co-Cu phase diagram at 830 °C based on 27 alloys. • No stable ternary phases found, only ternary extensions of binary phases observed. • Ultrafine-structured mixture of β-GaCo and β-GaCu//ζ-GaCu was found. • β-GaCo and β-GaCu mixture resembles a superalloy-like structure. [ABSTRACT FROM AUTHOR]

The work is focused on the experimental reinvestigation of the Al–Co phase diagram in vicinity of the Al 13 Co 4 family of phases. For this purpose several alloys were prepared with bulk compositions ranging between Al 71 Co 29 and Al 77 Co 23 . Experimental samples processed of the as-cast alloys were annealed for 330 h at various temperatures between 1070 and 1150 °C and subsequently rapidly cooled to fix their high-temperature microstructures. The annealing temperatures were selected with respect to the earlier published Al–Co phase diagrams. In the investigation X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy including both energy dispersive X-ray spectroscopy and electron backscatter diffraction were used. In the microstructures of as-annealed alloys various combinations of B2-AlCo, Al 5 Co 2 , Z-Al 3 Co, Y 1 -Al 13 Co 4 , Y 2 -Al 13 Co 4 , M-Al 13 Co 4 , O′-Al 13 Co 4 , and solidified liquid were identified. It was found out that the earlier published single-phase Y-area is comprised in fact of monoclinic Y 1 -Al 13 Co 4 and orthorhombic Y 2 -Al 13 Co 4 lamellas. From the thermodynamic point of view, Y 1 -Al 13 Co 4 and Y 2 -Al 13 Co 4 are stable and metastable phases, respectively. The O′-Al 13 Co 4 phase was identified at 1070 °C in the alloys where the occurrence of O-Al 13 Co 4 was expected. A modified partial Al–Co phase diagram was also proposed with respect to the experimental results obtained. [ABSTRACT FROM AUTHOR]

Abstract: The characterization of phases in Al73Mn27−x Fe x (x =2, 4 and 6) alloys was performed using X-ray diffraction, differential thermal analysis, and scanning electron microscopy enabling energy dispersive X-ray spectroscopy. Both the annealed and the thermally cycled states were studied. In the annealed states the occurrence of T-phase was expected, however it was confirmed for alloys Al73Mn25Fe2 and Al73Mn23Fe4 only. The annealing of the Al73Mn21Fe6 alloy probably led to the formation of decagonal quasicrystal (D). The T- and D-phases were found to be unstable at low temperatures. In the states after DTA the low temperature Al11(Mn,Fe)4 and γ2 phases were observed in the Al73Mn25Fe2 and Al73Mn21Fe6 alloys, while only the former phase was observed in the Al73Mn23Fe4 alloy. [Copyright &y& Elsevier]