Refinement of the Al-rich part of the Al-Cu-Re phase diagram and atomic model of the ternary Al6.2_{6.2}Cu2_{2}Re phase

Partial isothermal sections at 800, 650 and 590 °C were constructed for an Al-rich compositional range of Al–Cu–Re. The maximal solubility of Cu in the Al11Re4, h-Al4Re and l-Al4Re phases was found to be ∼6, 4.5, and 2.3 at% respectively, while the solubility of Re in the Al–Cu θ, η1 and ε2 phases was below 0.5 at%. Below 740 °C, a ternary hexagonal phase (P63, a = 1.1029 and c = 1.2746 nm) is formed in a small compositional range close to Al65Cu25Re10. Its structural model was deduced by direct methods applied on the precession electron diffraction tomography data

A study of the Al-Pd-Pt alloy system

The constitution of the Al−Pd−Pt alloy system was studied above 35 at.% Al at 700, 780, 900 and 1100 °C. The experiments revealed the formation of wide extensions of the binary Al−Pd and Al−Pt phases but no ternary phases. Continuous regions are probably formed between the isostructural phases Al4TM, Al21TM8, high-temperature AlTM, low-temperature AlTM and Al3TM5 (TM = Pd or Pt). The continuity between the Al3TM2 phases was revealed at 900 °C, while at 1100 °C the regions mutually extended from Al3Ni2 and Al3Pd2 are separated by the ternary extension of Al2Pt. The latter phase was found to dissolve up to 24 at.% Pd, which resulted in a sharp decrease of its Al concentration. The Al−Pd ε-phase was found to extend up to 18 at.% Pt at practically constant Al, while the Al−Pt ξ-phase was found to extend up to 7 at.% Pd

New complex intermetallic in the Al-Rh-Ru alloy system

A ternary orthorhombic phase (Pbma, a = 2.34, b = 1.62 and c = 2.00 nm) was revealed around the Al77Rh15Ru8 composition. It is structurally related to the Al-Rh and Al-Pd epsilon-phases. (C) 2011 Elsevier B.V. All rights reserved

An investigation of the Al-Rh-Ru phase diagram above 50at.%

Partial 1100, 1000, 900 and 700 degrees C isothermal sections of the Al-Rh-Ru phase diagram were determined. The isostructural binary AlRu and AlRh phases probably form a continuous beta-range of the CsCl-type solid solutions. The Al9Rh2 and C-Al5Rh2 dissolve up to 4.5 and 13 at.% Ru, while Al13Ru4 and Al2Ru dissolve up to 14.5 and 8 at.% Rh, respectively. A ternary orthorhombic structure (Pbma, a = 2.34, b = 1.62 and c = 2.00 nm) related to the Al-Rh epsilon-phases was revealed at the extension of the Al-Rh epsilon-phase area at compositions up to Al77Rh15Ru8. (C) 2011 Elsevier B.V. All rights reserved

Additive manufacturing of defect-free TiZrNbTa refractory high-entropy alloy with enhanced elastic isotropy via in-situ alloying of elemental powders

Abstract Laser powder-bed fusion (L-PBF) additive manufacturing presents ample opportunities to produce net-shape parts. The complex laser-powder interactions result in high cooling rates that often lead to unique microstructures and excellent mechanical properties. Refractory high-entropy alloys show great potential for high-temperature applications but are notoriously difficult to process by additive processes due to their sensitivity to cracking and defects, such as un-melted powders and keyholes. Here, we present a method based on a normalized model-based processing diagram to achieve a nearly defect-free TiZrNbTa alloy via in-situ alloying of elemental powders during L-PBF. Compared to its as-cast counterpart, the as-printed TiZrNbTa exhibits comparable mechanical properties but with enhanced elastic isotropy. This method has good potential for other refractory alloy systems based on in-situ alloying of elemental powders, thereby creating new opportunities to rapidly expand the collection of processable refractory materials via L-PBF