Phase Equilibria and Mechanical Properties in Multicomponent Al–Ni–X (X = Fe, Cr) Alloys

Abstract

The present study reports the microstructure evolution in multicomponent Al–Ni–X (X = Fe, Cr) alloys. The X-ray diffraction characterization technique and electron microscope attached with energy-dispersive spectroscopic analysis have been used to understand the structural and microstructural evolution in the present multicomponent Al–Ni–X (X = Fe, Cr) alloys. Al98.6Ni0.5Fe0.9 alloy shows the presence of (Al)ss, Al3Fe and Al9FeNi phases. It is observed that the microstructure of Al–Ni–Fe alloy shows the existence of primary dendritic phase of (Al)ss and two eutectics (i.e. globular eutectic: L → (Al)ss + Al3Fe and lamellar eutectic: L → (Al)ss + Al9FeNi). Al–Ni–Fe alloy shows superb compressive strength (~ 200 MPa) and plasticity (~ 70%) at room temperature, while the microstructure of multicomponent Al92Ni4Cr4 alloy exhibits the presence of dendritic phases of Al7Cr and Al3Ni plus ternary eutectic (i.e. L → (Al)ss + Al3Ni + Al7Cr). Al–Ni–Cr alloy shows good room temperature ultimate compressive strength (~ 300 MPa) and plasticity (~ 50%). It is important to note that there is no fracture during mechanical testing of investigated Al–Ni–X (X = Fe, Cr) alloys. © 2018, The Indian Institute of Metals - IIM.