Abstract The aim of this work is to study the non-membership function of a Prism Fuzzy Number. The non-membership function in the Prism fuzzy number is essential to reducing the level of uncertainty. In this artifact, we introduce a Prism Intuitionistic Fuzzy Number (PrIFN). The arithmetic operations, (\alpha, \beta) cut set, index of value, imprecision index, and theorems of Prism Intuitionistic fuzzy numbers are discussed with pertinent examples and results. There are numerous potential applications for the newly developed idea of a Prism Intuitionistic Fuzzy Number. To confirm and show the feasibility of the suggested method, a new grading technique is defined and an analysis of decision-making is illustrated.

A method is proposed for the determination of microstructural information, such as grain size and recrystallised fraction, directly from the BSE images. The approach exploits the channelling contrast present in the BSE images to extract maps analogous to grain reference orientation deviation (GROD) and kernel average misorientation (KAM) without the need for orientation information. These maps are then processed in order to determine the recrystallised fraction in an efficient manner. The BSE image series are acquired using the eCHORD acquisition setup: the sample is first tilted and a series of 30 images are acquired as the sample rotates. Compared to results obtained from orientation data, this method significantly reduces the acquisition and data processing time.

(Al,Si)3(Zr,Ti)-D022/D023 are phases that may form in aerospace and automotive aluminium alloys. The substitution of Zr/Ti in these solid solutions is widely reported in the literature; however, it remains relatively unexplored for Si. In this work, in situ precipitation of (Al,Si)3(Zr,Ti)-D022/D023 intermetallics was performed using Al-Si-Zr-Ti alloys. The precipitation, sedimentation and concentration of numerous intermetallic particles were accomplished by filtrating the residual molten aluminium using a temperature/pressure-controlled vessel adapted with a PoDFA filter. A combination of SEM, TEM, XRD and EMP analysis allowed the identification of (Al,Si)3(Zr,Ti)-D022/D023 intermetallics concentrated within α-FCC matrices of non-Si-doped (sample S2) and Si-doped (samples S4 and S6) alloys. EDS analysis confirmed that Zr and Ti substitute each other in the D022 and D023 phases, whereas Si substitutes in Al sites. Acceptance of Si inside the D023 phase was not expected according to FTlite (FactSage) and TCAL7 (Thermo-Calc) databases. Additionally, Si was found to enhance the formation of (Al,Si)3(Zr,Ti)-D022 intermetallics with high Zr-content, contrary to FactSage 7.3 predictions. TEM results showed intermetallic/FCC crystal coherency for samples S2 and S6, implying that these intermetallics acted as nucleation sites for the Al-phase due to their small lattice mismatch. Furthermore, Si site occupancy was calculated for both (Al,Si)3Ti-D022 and (Al,Si)3Zr-D023 phases via DFT, showing that sites 2b and 4e are the most favorable for Si occupation, respectively. Finally, a thermodynamic model is derived to describe Si substitution upon solidification. Experimental and numerical examinations indicate that Si substitution preferentially occurs in the D022 intermetallics compared to the D023 phase.

Cavitation erosion is a major challenge for marine and fluid machinery systems. This study investigated the erosion performance of two as-cast aluminium alloys exposed to acoustic cavitation in water at temperatures of 10–50 °C and those were then compared with an extruded wrought alloy tested specifically at the temperature of maximum erosion. The results showed that the as-cast A380 alloy displayed exceptional resistance to cavitation erosion, with the lowest mass loss and surface roughness. This finding suggests that the as-cast A380 alloy is a suitable choice for lightweight, high-performance components in applications where cavitation resistance is critical.

The clustering behaviors in two Al-Mg-Si alloys with and without Cu after different pre-aging and natural aging conditions were systematically quantified using microhardness, differential scanning calorimetry (DSC), and atom probe tomography. Cu addition slowed down the natural aging process after either solutionizing or pre-aging regardless of pre-aging temperature and time, and reduced the negative effect of post pre-aging natural aging on β” precipitation by changing the composition of the Mg and Si rich clusters. This work complements the limited literature on the effect of long natural aging, and provides insights into the impacts of alloy composition and storage time on precipitation behavior during subsequent artificial aging.

Aluminum alloys designed for laser powder bed fusion (L-PBF) often show a bimodal grain structure and a strong out-of-equilibrium character with heterogeneities developing at scales ranging from the melt pool, i.e. several hundred microns, down to sub-nanometer. When subjected to post-fabrication heat treatments, microstructural evolutions arise at all scales. Herein are established the relationships between microstructure and mechanical properties at room temperature of a novel Al-4Mn-3Ni-2Cu-1Zr alloy, designed for L-PBF and subjected to direct ageing. On the basis of a multiscale microstructural study using scanning-electron microscopy (SEM), automated orientation mapping in the transmission-electron microscope (TEM-ACOM), atom probe tomography (APT), and synchrotron small-angle X-ray scattering (SAXS), we discuss and weigh the role of multiple strengthening mechanisms to the high strength of the material. In the stress-relieved conditions (300 °C/4 h), the yield strength is about 320 MPa and solid solution strengthening accounts for nearly two third of the yield strength (∼200 MPa) thanks to a very high content of Mn retained in solid solution (> 1.5 at.%) and, to a lesser extent, grain boundary strengthening. After ageing at 400 °C/1 h, the yield strength reaches 410 MPa. The additional contribution is brought by precipitation strengthening by L12-ordered Al3Zr, and to a lesser extent, Mn-rich precipitates. The composite effect due to the large fraction of relatively fine (< 1 μm) intermetallic particles (∼20%) is highlighted and cannot be neglected. This work provides guidelines to further optimize the mechanical properties and thermal stability of Al-alloys designed for L-PBF.

Crack growth in stress corrosion cracking (SCC) in 7xxx Al alloys is an intermittent process, which generates successive crack arrest markings (CAMs) visible on the fracture surface. It is conjectured that H is generated at the crack tip during crack arrest, which then facilitates crack advancement through hydrogen embrittlement. Here, nanoscale imaging by 4D-scanning-transmission electron microscopy and atom probe tomography show that CAMs are produced by oxidation at the arrested crack tip, matrix precipitates dissolve and solute diffuse towards the growing CAM. Substantial homogenous residual strain remains underneath the fracture surface, indicative of non-localized plastic activity. Our study suggests that H induces crack propagation through decohesion.

Abstract It is reported that 65% of blade failure in turbo machinery is due to mechanical failures of the blades themselves [1]. The applied stress together with the higher temperatures can have a direct impact on the life of the impeller. It is therefore critical to evaluate the mechanical properties of materials and their durability at the relevant operating temperatures [1, 2]. In this study we will demonstrate the potential of different aluminum alloys to extend the life of a system by evaluating their durability over time at common operating temperatures. With appropriate testing that simulates the mechanisms involved at working conditions, one can benchmark the performance of different products. Comparisons between different alloys used as impellers in turboexpanders, turbo-blowers, turbopumps, turbochargers and superchargers are made. The most common products used in these applications is 2618-T8 and this alloy has been compared with the more recent 2027-T8 that is designed to withstand temperatures above 100°C. The applications demonstrated here for turbopumps and turbochargers will analyze the performance of 2618-T8 and be compared to the new 2027-T8. The microstructural differences between the two alloys are presented and will be related to the mechanical properties studied. Overall, 2027-T8 demonstrates improved performance at 150°C compared to 2618-T851 in all aspects of material performance: tensile properties, thermal stability, fracture toughness, fatigue and creep performance. These properties are all critical for choosing the appropriate alloy for an impeller or rotor in order to allow either improved performance or increased component lifetime due to over-performance of this newly studied alloy, 2027-T8.