Modeling and Experimental Results of Selected Lightweight Complex Concentrated Alloys, before and after Heat Treatment

Abstract

Lightweight complex concentrated alloys (LWCCA), composed of elements with low density, have become a great area of interest due to the high demand in a large number of applications. Previous research on LWCCAs was focused on high entropy multicomponent alloy systems that provide low density and high capability of solid solution formation. Present research introduces two alloy systems (Al-Cu-Si-Zn-Mg and Al-Mn-Zn-Mg-Si) that contain readily available and inexpensive starting materials and have potential for solid solution formation structures. For the selection of appropriate compositions, authors applied semi-empirical criteria and optimization software. Specialized modeling software (MatCalc) was used to determine probable alloy structures by CALPHAD, non-equilibrium solidification and kinetic simulations. The selected alloys were prepared in an induction furnace. Specimens were heat treated to provide stable structures. Physicochemical, microstructural, and mechanical characterization was performed for the selected alloy compositions. Modeling and experimental results indicated solid solution-based structures in the as-cast and heat-treated samples. Several intermetallic phases were present at higher concentrations than in the conventional alloys. Alloys presented a brittle structure with compression strength of 486–618 MPa and hardness of 268–283 HV. The potential for uniform intermetallic phase distribution in the selected alloys makes them good candidates for applications were low weight and high resistance is required.

Microstructure and Phase Formation of Novel Al80Mg5Sn5Zn5X5 Light-Weight Complex Concentrated Aluminum Alloys

“…These alloys are often called lightweight complex concentrated alloys (CCAs), low-density multi-principal elements alloys, entropic alloys, medium entropy aluminum alloys, etc. [17,[21][22][23][24][25][26] and are inspired by the high entropy concept, but expanding the compositional definition given at the beginning of HEAs.…”

“…Following the route to design non-equiatomic medium entropy alloys [27], the Al 65 Cu 5 Mg 5 Si 15 Zn 5 X 5 and Al 70 Cu 5 Mg 5 Si 10 Zn 5 Y 5 (X = Fe, Ni and Y = Cr, Mn, Zr, in at.%) alloys exhibited moderate plastic deformation and high compressive strength up to 644 MPa, and microhardness value up to 264 HV [22]. Recently, Mitrica et al studied several alloys in the Al-Cu-Si-Zn-Mg and Al-Mn-Zn-Mg-Si systems, where the Al 3.4 Cu 0.5 Si 0.2 Zn 0.5 Mg 0.2 and Al 3 Mn 0.2 Zn 0.3 Mg 0.7 Si 0.8 alloys exhibited the highest strength and hardness in each system [26].…”

Microstructural Evolution as a Function of Increasing Aluminum Content in Novel Lightweight Cast Irons

“…In this way, novel materials such as complex concentrated alloys, medium/high entropy alloys, aluminum-based hybrid composites, etc. has been developed in the last years [1][2][3][4][5].…”

Researches Regarding Structural Characteristics of a New Complex Concentrated Alloy Obtained by Rapid Solidification

“…The obtaining process of CCAs is more complex compared with traditional alloys, because of the large number of possible combination elements that are mixed together [1]. The multicomponent character of CCAs and the main core effects influence the microstructure and the potential of supporting improved mechanical properties at high temperatures [2]. The properties of the CCAs depend of each element characteristics and their concentration, so that by modifying the composition, the properties and structural particularities of the alloy are significantly different from the initial one [3].…”

“…In this context, a rigorous selection process was applied to identify the most suitable chemical composition and proportion of the used elements. By applying thermodynamic and kinetic models and MatCalc computer simulations it was determined an optimal composition of the alloys [2]. These processes are followed by elaboration phase that is performed using the meltspinning equipment, on different rotation rates, between 500 and 1500 rpm.…”