Heusler Al-Cu-Fe alloys, known for their unique physical properties, find application in various fields, including microelectronics and sensors. However, their mechanical characteristics, especially susceptibility to aging, wear and residual stress formation, require detailed study to ensure reliable operation under real operating conditions.
The effect of aging on the mechanical properties of the Heusler Al-Cu-Fe alloy was studied by heat treating samples at different temperatures and holding times. It was found that aging changes the microstructure of the alloy, in particular, to the release of secondary phases. This, in turn, affects the hardness, tensile strength and plasticity of the material. Optimum aging modes allow achieving the best combination of strength and plasticity characteristics.
In this work, the ferromagnetic Al-Cu-Fe Heusler alloy was subjected to heat treatment at 300°C for different durations: 0.5 h, 1 h, 1.5 h, 2 h and 2.5 h. After that, the structural characteristics, mechanical parameters, residual stress level and wear resistance of the obtained samples were analyzed. The obtained data indicate a significant effect of the phase precipitation process on the mechanical properties and wear resistance of the Heusler alloy.
It was found that an increase in the density of the precipitated particles leads to an increase in the hardness and wear resistance of the samples. These precipitates are lamellar structures enriched in copper and Al-Cu. Analysis of the precipitate density revealed two pronounced peaks for the Al2Cu phase, observed during holding for 90 and 150 minutes for the annealed samples.
The wear resistance of Heusler Al-Cu-Fe alloy was studied using various tribological testing methods. The results showed that aging can either improve or worsen wear resistance, depending on the heat treatment conditions. An important factor is the formation of an oxide film on the surface of the material, which can act as a protective layer.
The residual stress analysis of Heusler Al-Cu-Fe alloy was performed using X-ray diffraction. It was found that ageing can lead to changes in the nature and magnitude of residual stresses. This is due to differences in the thermal expansion coefficients of the various phases present in the alloy. Residual stress control is important to prevent cracking and improve the fatigue strength of the material.
Author: Fazil Husem, Fatma Meydaneri Tezel and Muhammet Emre Turan
Institute: Karabuk, Türkiye