Formation of Quasicrystalline Phases and Their Close Approximants in Cast Al-Mn Base Alloys Modified by Transition Metals

Abstract

Abstract:The aim of the presented research was to study the influence of Cr, Co, Ni, and Cu additions on the formation of quasicrystalline particles in the 94Al-6Mn base alloy during casting at intermediate cooling rates. Based on the obtained results, Cu and Ni enhance quasicrystalline phase nucleation compared to the unmodified binary composition. In the case of Cu addition, formation of a quasicrystalline phase takes place along whole thickness of the prepared casting, but its fraction and morphology depends on the cooling rates present in different parts of the sample. Based on the previous works on the beneficial effect of Fe addition, a quaternary alloy containing both Fe and Cu was prepared to evaluate the effect of the simultaneous presence of these elements on the microstructure of the obtained castings.

Multi-scale microstuctural investigation of a new Al-Mn-Ni-Cu-Zr aluminium alloy processed by laser powder bed fusion

“…The XRD patterns displayed in Figure 5b and Figure 5c can be respectively indexed with a good agreement as the monoclinic Al9Co2-structure type and the orthorhombic Al60Mn11Ni4-structure type. These structures are consistent with the presence of the Al9Ni2 and Al60Mn11Ni4 phases earlier identified in others Al-alloys [38]- [39] but never reported in Al-alloys produced by additive manufacturing. Interestingly, the Al60Mn11Ni4 phase exhibits a large lattice parameter with local icosahedral packing.…”

Ageing of Al-Mn-Cu-Be Alloys for Stimulating Precipitation of Icosahedral Quasicrystals

“…in Figure 2a. Its presence testified the existence of an additional phase at the sample centre, belonging probably to Al15Mn3Be2 [6] or any other metastable phases found in Al-Mn-Cu alloys by Stan-Glowinska [23]. The highly alloyed Al95.4Mn1.8Cu1.6Be1.2 attained the highest hardness in the as-cast state due to the higher phase fraction of IQC and Θ-Al2Cu (Figure 3a).…”

“…in Figure 2a. Its presence testified the existence of an additional phase at the sample centre, belonging probably to Al 15 Mn 3 Be 2 [6] or any other metastable phases found in Al-Mn-Cu alloys by Stan-Glowinska [23].…”

“…In Al-Mn-Cu alloys, decagonal quasicrystals can form upon solidification [23,40]. The decagonal Al-Mn-Cu phase is closely related to the equilibrium phase τ 1 .…”

Morphological and microstructural characterization of Al95Fe2 Cr2 Ti1 powders produced by two different gas atomizers

“…The Al 13 (Cr,Fe) 2,4 phase can be recognized as a phase precedent of the flower-like phase. This phase is rich in chromium and iron as proved by EDS and is well-known as an approximant of the QC phase common in Al-Cr-Fe-X alloys [24][25][26][27]. These results suggest that most of the PH powder particles (GMR= 1.7) underwent cooling rates enough to form a high amount of QC phase, whilst the most of the PS powder (GMR = 1.0) underwent cooling rate that provided a longer solidification time with the formation of intermetallic phases as Al 3 Ti 1 /Al 23 Ti 9 phase.…”