Microstructure and Mechanical Properties of Rapidly Solidified Al-Fe-Ni-Mg Alloys

2011 ◽  
Vol 674 ◽  
pp. 165-170 ◽  
Author(s):  
Anna Kula ◽  
Ludwik Blaz ◽  
Makoto Sugamata

Rapid solidification (RS) combined with following mechanical consolidation of RS powders is considered as a valuable commercial method for the production of a wide range of metallic materials having fine-grained structures. Reported research results for various alloys demonstrate better compositional homogeneity, smaller grain size and relatively fine precipitates distributed homogenously in RS alloys than that for the materials produced by conventional metallurgical processing. The effect of rapid solidification on the microstructure and mechanical properties of selected Al-Fe-Ni-Mg alloys have been investigated. The basic item of the research work was obtaining aluminum PM materials strengthened by highly-dispersed transition metal compounds and aluminum-magnesium solid solution. Rapid solidification (RS) of Al-4Fe-4Ni and Al-4Fe-4Ni-5Mg alloys was performed by means of gas atomizing of the molten alloy and the spray deposition on the rotating water-cooled copper roll. Using typical powder metallurgy (PM) methods, i.e. cold pressing, vacuum degassing and hot extrusion, the RS-flakes were consolidated to the bulk PMmaterials. For comparison purposes, the conventionally cast and hot extruded Al-4Fe-4Ni and Al-4Fe-4Ni-5Mg alloys were studied as well. Mechanical properties of as-extruded materials were examined by compression tests performed at 293 K – 873 K. It was found that relatively high strength of as-extruded PM materials was accompanied by high ductility of samples deformed by hot compression test. Structural observations confirmed beneficial influence of rapid solidification on effective refining of intermetallic compounds, although some inhomogeneity of fine precipitates distribution was observed. Nevertheless, it was considered that an effective increase of the microhardness and strength of tested RS materials mostly result from achieved dispersion of structural components and can be intensified by solid solution hardening due to Mg-addition.

2012 ◽  
Vol 186 ◽  
pp. 279-282 ◽  
Author(s):  
Anna Kula ◽  
Ludwik Blaz ◽  
Makoto Sugamata

Rapid solidification (RS) of Al-2Fe-2Ni-5Mg alloy and following mechanical consolidation of powders by means of powder metallurgy (PM) methods was used with success to produce a bulk RS-material. RS powders were manufactured using an inert gas atomizing of the molten alloy and the spray deposition on the rotating water-cooled copper roll. Rods of 7 mm in diameter were received by means of the cold pressing of the flakes, vacuum degassing and hot extrusion method. For comparison purposes, the conventionally casted and hot extruded Al-2Fe-2Ni-5Mg alloy was tested as well. Mechanical properties of as-extruded materials were examined at 293 K – 873 K by compression tests performed at constant true strain rate of 5·10-3[s-1]. It was found that relatively high strength of as-extruded RS/PM material was accompanied by the high ductility of the samples deformed by hot compression tests. It was noticed that the most effective solution strengthening due to particles refining was observed at low deformation temperatures. Rising the test temperatures above ~ 420 K, was found to result in reduction of the flow stress to the values received for the industrial material (IM).The formation of coarse primary intermetallic compounds, which is typical for IM material, was effectively reduced for RS material. However some inhomogeneity of fine precipitates distribution in RS/PM material was observed. Nevertheless, it was considered that both solid solution hardening due to Mg addition and the dispersion strengthening due to refining of intermetallic compounds substantially increase the mechanical properties of the RS/PM material.


2014 ◽  
Vol 1036 ◽  
pp. 101-105
Author(s):  
Gheorghe Buluc ◽  
Iulia Florea ◽  
Oana Bălţătescu ◽  
Costel Roman ◽  
Ioan Carcea

This paper presents the microstructure and the mechanical properties of FeNiCrCuAl high entropy alloys. The microstructure and mechanical properties of the annealed FeNiCrCuAl high entropy alloys were investigated using scanning electron microscopy, and X-ray diffraction. High entropy alloys have been known as a new type of materials and have been defined as having five or more principal elements, each one having a concentration between 5 and 35 at.%. Previous researches show that HEAs can be processed to form simple solid solution structures instead of intermetallics and other complicated compounds. This phenomenon is commonly attributed to the high configurational entropy in the solid solution state of HEAs. Furthermore, HEAs have also exhibited interesting properties such as high hardness and high strength, good thermal stability outstanding wear and oxidation resistance which offer great potential for engineering applications. The HEA systems explored in the past decade show that metallic elements are the most commonly used, e.g. Al, Cr, Fe, Co, Ni, Cu,Ti, etc. A wide range of HEAs exhibit high hardness, high strength, distinctive electrical and magnetic properties, high-temperature softening resistance, as well as favorable combination of compression strength and ductility. This combination of properties and the particular structures of HEAs are attractive for a number of potential engineering applications.


2019 ◽  
Vol 38 (2019) ◽  
pp. 892-896 ◽  
Author(s):  
Süleyman Tekeli ◽  
Ijlal Simsek ◽  
Dogan Simsek ◽  
Dursun Ozyurek

AbstractIn this study, the effect of solid solution temperature on microstructure and mechanical properties of the AA7075 alloy after T6 heat treatment was investigated. Following solid solution at five different temperatures for 2 hours, the AA7075 alloy was quenched and then artificially aged at 120∘C for 24 hours. Hardness measurements, microstructure examinations (SEM+EDS, XRD) and tensile tests were carried out for the alloys. The results showed that the increased solid solution temperature led to formation of precipitates in the microstructures and thus caused higher hardness and tensile strength.


2016 ◽  
Vol 850 ◽  
pp. 511-518 ◽  
Author(s):  
Hai Jun Liu ◽  
Lie Jun Li ◽  
Jian Wei Niu ◽  
Ji Xiang Gao ◽  
Chuan Dong Ren

The effects of Mg and Cu additions with different contents on the mechanical properties of Al-Si alloy prepared by indirect squeeze casting have been experimentally investigated. The microstructure and mechanical properties of as-cast and T6-treated Al-Si-Cu-Mg alloys were tested by OM, SEM, DSC and tensile measurement, where the samples were produced by artificial aging at 180°C for 8 h after solution treatment at 540°C for 4 h. It has been found that for the as-cast alloys, with increasing contents of Mg and Cu the tensile strength (UTS) and yield strength (YS) increased, while the percentage elongation (El) decreased. And the optimal mechanical properties of Al-Si-Cu-Mg alloys were obtained under the content ratio of Cu/Mg within 4, where the UTS and El reached 426 MPa and 6.3% after T6 treated, respectively.


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