Al-Cu-Fe quasicrystals, known for their high hardness and oxidation resistance, are promising materials for various applications. However, their brittleness limits their widespread use. In this paper, the effect of tin reinforcement on the structure, microstructure, and mechanical properties of Al-Cu-Fe quasicrystalline alloy obtained by powder metallurgy is investigated.
Al-Cu-Fe and Sn powders were mixed in different proportions and subjected to pressing and sintering. X-ray diffraction (XRD) analysis showed the preservation of the quasi-crystalline Al-Cu-Fe phase after sintering, as well as the formation of Al-Sn and Cu-Sn intermetallic compounds. Microstructural analysis using scanning electron microscopy (SEM) revealed a uniform distribution of tin particles in the quasi-crystalline matrix.
The introduction of tin resulted in a significant improvement in the ductility of the Al-Cu-Fe alloy. Vickers hardness measurements showed a decrease in hardness with increasing tin content, indicating plasticization of the quasi-crystalline matrix. The strengthening mechanism is explained by dispersion strengthening caused by tin particles and intermetallic compounds that impede dislocation movement.
The results of this work demonstrate that tin reinforcement is an effective way to increase the plasticity of Al-Cu-Fe quasicrystals without significantly deteriorating their hardness. The resulting composite materials can be used as wear-resistant coatings and structural elements.
In this paper, we investigate the process of fabrication of tin-reinforced Al-Cu-Fe composites with icosahedral quasicrystalline (IQC) structure. The method of mechanical grinding followed by hot pressing and sintering without pressure was used. The structure, microstructure and mechanical properties of the obtained nanocomposite powders and bulk samples were studied in detail using the methods of X-ray diffraction, optical microscopy, scanning electron microscopy and hardness measurement. X-ray diffraction patterns confirmed the presence of the IQC phase, λ-Al13Fe4 and the B2-type crystalline phase of Al(Cu, Fe) in both ground and sintered samples. The icosahedral structure is preserved even after long-term grinding and sintering. The structural changes occurring during mechanical grinding affect the behavior of IQC-Sn nanocomposite powders under indentation. Microhardness varies from 5.3 to 7.3 GPa.
The behavior of IQC-Sn nanocomposites obtained by pressureless sintering and hot pressing methods is investigated. The fracture toughness of the IQC-10Sn sample obtained by hot pressing is approximately 1.92 MPa √m, which is 22% higher than that of cast and annealed IQC. The increase in fracture toughness is mainly due to the inhibition of crack propagation by tin particles. The obtained results indicate the possibility of creating IQC-Sn composites with an optimal combination of hardness and fracture toughness using powder metallurgy methods.
Author: Yagnesh Shadangi, Vikas Shiva,Kaushik Chattopadhyay, Nilai Krishna Mukhopadhyay
Institute: Department of Metallurgical Engineering, Indian Institute of Technology (BHU), Varanasi 221005, India, Materials Processing Group, Materials Science Department, CSIR National Metallurgical Laboratory, Jamshedpur 831007, India