Influence of Ho and Hf on the microstructure and mechanical properties of NiAl and NiAl-Cr(Mo) eutectic alloy

Optimization of the Microstructure and Mechanical Properties of a Laves Phase-Strengthened Hypoeutectic NiAl/Cr(Mo,W) Alloy by Suction Casting

“…Therefore, it has been thought as the potential candidate for high temperature structure materials subjected to the severe oxidation and corrosion [7,8]. According to previous researches [9,10], NiAl has…”

Microstructural verification of the theoretically predicted morphologies of the NiAl–Cr pseudo-binary alloy systems and NiAl–Cr eutectic structure modification by Mo addition

“…Argon (industrial purity) was used as protective atmosphere and a Ti gutter was in all cases melted first in order to further reduce oxygen contamination phenomena. This manufacturing process is considered to be a standard practice for production HEAs and has been widely used in other research efforts as for example in [20]. The actual composition was checked using EDS mapping in the SEM in at least 3 different locations of lower magnification and all fell within the measured compositions presented in Tables 1 and 2.…”

“…In the case of Ho and Hf addition [19] the researchers distinguished their synergetic action which caused multiple intermetallic phase precipitation sequences, morphological alterations of the eutectic structures and primary phases and improvement in micro-hardness and strength. In the case of Hf and Dy additions [20] the authors showed apart formation of various precipitates, a possibility of microstructural refinement and tuning leading to a significant improvement of the mechanical response.…”

“…Wang et al produced NiAl-Cr(Mo) hyper-eutectic alloys using directional solidification techniques aiming to lamellar solidification of Cr(Mo) in the eutectic micro-constituent [18]. Additionally, Zheng et al [19] and Sheng et al [20] has extensively investigated the effect of elemental additions, such as Ho and Hf in the first case and Hf and Dy in the second, on the microstructure and the mechanical properties of the basic NiAl-Cr(Mo) core. In the case of Ho and Hf addition [19] the researchers distinguished their synergetic action which caused multiple intermetallic phase precipitation sequences, morphological alterations of the eutectic structures and primary phases and improvement in micro-hardness and strength.…”

Microstructural Characteristics and Mechanical Properties of a Nb/Nb5Si3 based Composite with and without Directional Solidification

“…Based on the recent investigations [22,23], the appropriate rare earth addition could increase the cohesion of phase boundary. Moreover, the regular and fine arrangement of ductile and strengthening phases could be helpful to the ductility and strength simultaneously [24,25]. Therefore, in the present research the dysprosium (Dy) was added in the Nb-Si-Ti-Al-Cr-Hf alloy and fabricated by the conventional casting (CC) to obtain the CC Nb/Nb 5 Si 3 based composite.…”