Properties Of Alloys Research Articles

Study on the effect of hafnium on mechanical properties of high-magnesium aluminum alloys with added transition metals after cold rolling and final annealing

Study on the effect of hafnium on mechanical properties of high-magnesium aluminum alloys with added transition metals after cold rolling and final annealing

Oxide/metal interface enhancement for improved dispersion strengthening mechanism in oxide-strengthened tungsten

The addition of secondary ceramic particles has shown to be effective in enhancing the mechanical properties of tungsten alloys. The diverse strengthening effects observed with various secondary particles necessitate further investigation. Herein, three ultrafine-grained, oxide-dispersed-strengthened tungsten alloys were prepared using solution combustion synthesis combined with low-temperature sintering. We thoroughly investigated the influence of Al2O3, La2O3, and Y2O3 on the microstructure and mechanical properties of tungsten, as well as their respective strengthening mechanisms. A detailed comparison revealed discrepancies between the yield strength experimentally measured and the theoretically predicted strength based on conventional grain refinement strengthening and dispersion strengthening theories, highlighting the significance of the intrinsic nature of dispersed oxides. Electron microscopy analysis and density functional theory calculations revealed that, compared to other oxides, the heterogeneous interface of Al2O3 with W exhibited minimal lattice distortion and the highest work of separation, resulting in a robust interface bonding. The prepared W–Al2O3 alloy showed exceptional performance with Vickers hardness HV0.2 of 698.9 and yield strength of 2488 MPa. Its yield strength surpassed that of W–Y2O3 and W–La2O3 alloys, as well as other commonly reported refractory metal materials.

Fabrication and investigation of microstructural, mechanical and wear properties of in situ ZrB2/fly ash/AA7075 hybrid composite

This research explores the microstructural, mechanical and wear characteristics of hybrid aluminum metal matrix composites (HAMMCs). Initially ZrB2 is fabricated by melt reaction and then fly ash incorporated into the aluminum composite melt as secondary reinforcements to fabricate HAMMCs through the ultrasonic agitated stir casting method. Micrographic and phase analysis of the HAMMCs and base alloy is conducted x-ray Diffraction (XRD), and Energy-Dispersive x-ray Spectroscopy (EDS). A wear test was conducted to study the wear properties of alloy and hybrid composite material. The generated wear scar was analyzed using a profilometer to find the wear rate. The tensile strength and hardness of the hybrid aluminum metal matrix composites (HAMMCs) improved remarkably as compared to base alloy. The wear resistance of the fabricated composite also increases on increasing the in situ ZrB2 up to 3 weight fractions.

Iron phosphate nanoparticles as oil additives to enhance anti-wear properties

In recent years, nanomaterial lubricant additives have been widely studied in tribology. In this work, a new iron phosphate (FeP) nanoparticle was synthesized to enrich the anti-wear oil-based additives for titanium alloys. A series of tribological experiments were conducted using a reciprocating ball-on-disc tribometer. It has been confirmed that, as additives in polyalphaolefin 8 (PAO8), FeP nanoparticles exhibit excellent friction-reducing and anti-wear properties for TA5 titanium alloys. Compared with the pure PAO8, the friction coefficient (COF) and wear rate (WR) can be significantly reduced by 69.89 % and 99.57 % at a concentration of 30 wt%. The SEM and EDS confirmed that FeP nanoparticles can play a surface repair role and deposit on the titanium alloy surface to form a deposition layer, which was the key to anti-wear property. Besides, XPS characterization demonstrated that the formation of the deposition layer was attributed to the P–O–Ti bond at the interface, through which the phosphate in FeP can bind to and adsorb on the titanium alloy surface. This deposition layer containing FeP can greatly reduce the adhesive wear of the titanium alloy. Meanwhile, the rolling effect of nanoparticles inside the deposition layer promoted the friction-reduction.

Features of functional behavior of TiNi shape memory alloy after uniaxial high speed magnetic pulse tension

This study investigates the influence of high strain rate on the functional properties of TiNi shape memory alloys. Specimens were deformed in tensile mode using a magnetic pulse loading setup equipped with an optical system to measure the loading time. The technique allows to obtain different strain rates without changing the working part of the specimens, i.e. the residual strains remained the same. The results show that the shape memory effect decreases by 10–25% with increasing strain rate. However, a high strain rate has a positive effect on the two-way shape memory, which increases by 10–25%.

Research on the Preparation of Zirconia Coating on Titanium Alloy Surface and Its Tribological Properties

Titanium alloys have been widely used in aerospace and other fields due to their excellent properties such as light weight and high strength. However, the extremely poor tribological properties of titanium alloys limit their applications in certain special working conditions. In order to improve the tribological properties of titanium alloys, the zirconia coatings were prepared on the surface of a TC4 titanium alloy using the discharge plasma sintering method in this article. The influence of sintering parameters on properties such as density, adhesion, hardness, and phase composition, as well as tribological properties (friction coefficient, wear rate) were investigated, and the influence mechanism of the coating structure on its mechanical and frictional properties was analyzed. The results showed that, with the increase in sintering temperature, the density, bonding strength, and hardness of the zirconia coating were significantly improved. The zirconia coating prepared at a sintering temperature of 1500 °C and a sintering time of 20 min had the lowest friction coefficient and wear rate, which are 0.33 and 6.2 × 10−8 cm3·N−1·m−1, respectively. Numerical analysis showed that the increase in temperature and the extension of time contributed to the extension of the diffusion distance between zirconia and titanium, thereby improving the interfacial adhesion. The influence mechanism of different sintering temperatures and sintering times on the wear performance of zirconia coatings was explained through Hertz contact theory.

Phase stability and mechanical properties of the six-principal element TiVNbCrCoNi alloys

This study designed a series of six-principal element TiVNbCrCoNi alloys according to the maximum entropy principle under the constraint of valence electron concentration (VEC). The phase stability and mechanical properties were investigated. It was showed that at VEC levels below 5.2, the body-centered cubic (BCC)-structured solid-solution phase remained stable at room temperature. As VEC exceeded 8.0, the face-centered cubic (FCC)-structured solid-solution phase stabilized. In the VEC range of 5.2–8.0, (Co, Ni)Ti and Ni3Nb intermetallic compounds formed combining with the solid-solution phases. Both yield strength and ductility increased with increase of VEC in the BCC-structured solid-solution alloys. The phase stability was elucidated through First-principle and thermodynamic calculations, while the evolution of mechanical properties of solid-solution alloys was evaluated in terms of multiple parameters. The thermodynamic calculation achieved satisfactory accuracy after being adjusted to utilize atomic bond enthalpy instead of atomic electronegativity difference.

Synergetic enhancement of ultimate strength and damping properties by pore structure in novel porous Cu-Al-Mn shape memory alloy

To meet the higher device vibration reduction requirements, novel porous Cu71Al18Mn11 shape memory alloys (SMAs) with controllable porosity were prepared using Cu, Al, and Mn elemental powders as raw materials. To further enhance the strength and damping performance of SMAs, a low-temperature reactive synthesis combined with spark plasma sintering (LTRS+SPS) process was used. In this paper, the effects of LTRS+SPS process on pore structure and texture, compressive strength, and damping properties of porous Cu71Al18Mn11 alloy were studied. The outcomes indicated that LTRS+SPS process can effectively improve both compressive strength and damping properties. The associated closed pore structure caused by this process and the second phase γ2 phase formed by element diffusion result in a variety in compressive strength from 324.6 MPa to 617.9 MPa, which were 3.9 times that of the comparable porosity alloy with alloy powder as raw material by vacuum sintering. Meanwhile, the damping value changed from 0.27 to 0.10, which was 4.5 times that of the homogeneous dense alloy. The increase in damping property is caused by the increase of motionable interfaces in the matrix for the introduction of pores, which leads to the increase of energy dissipation. Besides. the interaction between the second phase γ2 and dislocation contributes to the improvement of damping, as well as the compressive strength. These findings in this paper provide new insights and references for the structural design and microstructure design of high-performance Cu-based alloys.

Higher laser power improves strength but reduces corrosion resistance of Mg WE43 processed by powder bed fusion

Powder bed fusion – laser beam (PBF-LB) of Mg alloys provides new possibilities for the production of complex structures with optimized designs, both for weight reduction in aerospace applications, as well as for patient-specific implants in orthopedic applications. However, even though numerous studies have been carried out on the topic, the influence of the individual PBF-LB process parameters on the microstructure and resulting material properties of Mg alloys remains ambiguous. Thus, this study aims to investigate the influence of laser power on the surface roughness, microstructure and resulting key material properties, namely corrosion resistance and mechanical performance. Samples were produced by PBF-LB from gas atomized Mg-4%Y-3%Nd-0.5%Zr (WE43) alloy powder, using three different laser powers: 60 W, 80 W, and 90 W. Contrary to expectation, the 90 W samples exhibited the highest degradation rate, while 60 W samples had the lowest, despite the latter having highest surface roughness and large internal pores. The higher degradation rate for the 90 W samples was instead found to stem from the near-surface microstructure. The higher energy input and subsequently reduced grain size, resulted in an increased amount of second phase precipitates than for the 60 W samples, thereby increasing the tendency for pitting via microgalvanic corrosion. For the tensile strength and elongation at break, the opposite trend was observed. Here, a reduction in grain size and an increase in precipitates for the 90 W samples were found to be beneficial. In conclusion, a definite influence of laser power on the formation of microstructure was observed, ultimately impacting the resulting corrosion and tensile properties of WE43. Future work should investigate the influence of other PBF-LB process parameters, with the aim of establishing an optimum balance between corrosion resistance and mechanical properties.

Microstructure evolution and mechanical properties for oxygen-rich ZrTiAlV alloy during in-situ semi-solid processing

Oxygen-rich ZrTiAlV alloy reinforced by spherulite ZrO phase was prepared by in-situ semi-solid processing. The results of high temperature (500°C) mechanical properties test confirmed that alloy elongation after semi-solid processing at 1500°C was close to that for the as-forged material, whereas yield and tensile strength were increased by 66.4% and 30.8%, respectively. SEM and EBSD results confirm that morphology selection of non-equilibrium growth is mainly controlled by the initial core shape, with dendrites always growing along the <110> direction following the Twin-Plane-Reentrant-Edge mechanism. Improved alloy strength is attributed to fine grain strengthening and precipitation strengthening caused by the ZrO phase, and α phase spheroidization ensures alloy plasticity. We also propose a crack deflection toughening mechanism for the alloy.

INFLUENCE OF ELECTROLYSIS CONDITIONS ON THE COMPOSITION OF ELECTROLYTIC COMPOSITE COATINGS BASED ON COBALT

The composite coatings electrodeposition with the refractory metals with cobalt makes it possible to obtain a coating with a unique combination of physicochemical properties that are unattainable when using other application methods. One of the reasons for the limited use of the electrolytic method of coating with such composites is the difficulty of controlling the process. The properties of alloys of the iron subgroup with refractory metals and composites depend not only on the chemical composition (the content of the refractory component) but also on the deposition conditions. By varying the composition of the electrolyte in galvanostatic mode it is impossible to obtain high-quality composite coatings with a high content of refractory components and current efficiency. As an alternative, it was suggested the use of pulsed electrolysis mode that allows to improve the producing of composite coatings. The process of formation of composite electrolytic coatings based on cobalt Co-W-ZrO2 on a copper substrate in pulse mode with a diphosphate-citrate electrolyte was investigated. The effect of current density, pulse duration and frequency on the coating composition, surface morphology, and current efficiency of compositional electrolytic coatings based on cobalt with refractory metals. An increase in current density causes a decrease in the content of refractory metals in compositional electrolytic coatings and an increase in oxygen content. The resulting coatings differ in a uniformly developed surface without cracks, which provides a sufficiently high adhesion. It is established that the size of the globe on the surface of the alloy decreases with increasing current density to 10 A/dm2. The control of the composition of Co-W-ZrO2 galvanic alloys in a quite wide range of alloying components concentrations is being achieved by varying the parameters of the pulse electrolysis, which allows adapting of the deposition technology to the needs of the modern market.

STUDY ON MAGNETIC PROPERTIES OF FeCoPSiBCu AMORPHOUS ALLOY BY EMPIRICAL ELECTRON THEORY

In this study, a new evaluation method was investigated for the magnetic properties of the amorphous alloys by comparing the experimental results with the theoretical calculations. First, The (Fe[Formula: see text]Co6P[Formula: see text]Si[Formula: see text]B[Formula: see text])[Formula: see text]Cux ([Formula: see text]–0.5) amorphous ribbons were prepared by melt spinning method. Then, the magnetic properties of the prepared amorphous alloys were measured as 165.86–147.04[Formula: see text]emu/g, respectively. On the other side, we analyzed the valence electron structure and obtained the magnetizations as 159.92–158.77[Formula: see text]emu/g by calculating the magnetic moments of unit cells based on empirical electron theory (EET) of solids and molecules. Through comparing the magnetic properties of the calculations with the measurements, we found that the differences between the calculations and the measurements are less than 12% for all samples, meeting the first approximation requirement. Moreover, with the addition of Cu, the change trends both in the calculated and measured magnetic properties are also consistent. These results prove that it is feasible to calculate the magnetic property of the amorphous alloy from the valence electron level using EET, which provides a new method to investigate the soft magnetic property of the amorphous alloy instead of the real measurement.

Influence of Zr Microalloying on the Microstructure and Room-/High-Temperature Mechanical Properties of an Al-Cu-Mn-Fe Alloy.

Here, 0.3 wt.%Zr was introduced in an Al-4 wt.%Cu-0.5 wt.%Mn-0.1 wt.%Fe alloy to investigate its influence on the microstructure and mechanical properties of the alloy. The microstructures of both as-cast and T6-treated Al-Cu-Mn-Fe (ACMF) and Al-Cu-Mn-Fe-Zr (ACMFZ) alloys were analyzed. The intermetallic compounds formed through the casting procedure include Al2Cu and Al7Cu2Fe, and the Al2Cu phase dissolves into the matrix and re-precipitates as θ' phase during the T6 process. The introduction of Zr results in the precipitation of L12-Al3Zr nanometric precipitates after T6, while the θ' precipitates in ACMFZ alloy are much finer than those in ACMF alloy. The L12-Al3Zr precipitates were found coherently located with θ', which was assumed beneficial for stabilizing the θ' precipitates during the high-temperature tensile process. The tensile properties of ACMF and ACMFZ alloys at room temperature and elevated temperatures (200, 300, and 400 °C) were tested. Especially, the yield strength of ACMFZ alloys can reach 128 MPa and 65 MPa at 300 °C and 400 °C, respectively, which are 31% and 33% higher than those of ACMF alloys. The strengthening mechanisms of grain size, L12-Al3Zr, and θ' precipitates on the tensile properties were discussed. This work may be referred to for designing Al-Cu alloys for application in high-temperature fields.

Investigating the influence of rotating magnetic field (RMF) on intermetallic compound crystallization, thermal and mechanical properties in lead-free Sn-Ag-Cu solder alloys during solidification

This research delves into the effectiveness of using rotating magnetic field (RMF) during the solidification process of Sn-3.5 wt% Ag-0.7 wt% Cu (SAC 357) alloy. The main goal is to evaluate the effect of RMF on the crystallization of intermetallic compounds (IMCs), as well as to study its implications for the thermal properties and creep resistance of the resulting alloy. It is found that the application of the RMF has a significant promotion effect on the improvement in the grain structure of the primary AgSn phase within the directionally solidified SAC 357 alloy. With the application of RMF, the morphology of the primary AgSn phase transformed from developed dendritic-like to fine needle-like, accompanied by a decrease in grain size, but shows no discernible impact on their composition. This observation is attributed to the influence of Lorentz force and thermo-electromagnetic convection. The implementation of a rotating magnetic field (RMF) resulted in notable enhancements in the thermal properties of the SAC357 solder alloy. Specifically, RMF application led to reductions in both the pasty range and melting temperatures, accompanied by a decrease in undercooling compared to conditions without stirring.The SAC357 alloy, when modified with a magnetic field, demonstrated the longest creep rupture time and higher creep resistance compared to those not subjected to magnetic field modification. This research endeavor aims to address a notable gap in our understanding concerning the behavior of SAC357 solder alloys when subjected to a Rotating Magnetic Field (RMF).

Influence of Various Melt Shearing Speeds on Macrostructure, Microstructure, and Tensile Properties of A380 Aluminum Alloy

Influence of Various Melt Shearing Speeds on Macrostructure, Microstructure, and Tensile Properties of A380 Aluminum Alloy

Thermal, microstructural, wettability and mechanical properties of Sn1.0Ag0.5Cu composite solder modified with Ti nanoparticles

In this study, highly active Ti nanoparticles (Ti NPs) were added to a low silver Sn-1.0Ag-0.5Cu (SAC105) solder. The thermal, microstructural, interfacial, wettability and mechanical properties of SAC105-xTi NPs (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 wt%) solders were investigated. The results showed that adding Ti NPs had little effect on the melting point and melting point range of SAC105 solder alloy. The solder alloy containing 0.2 wt% Ti NPs had the lowest coefficient of thermal expansion (CTE) of 21.1 × 10−6 m/°C. The SAC105–0.4 Ti NPs solder has a contact angle of 24.3°, 7.57° lower than the SAC105 solder. However, Ti NPs deteriorate the surface of the solder joint as they oxidize to produce TiO2 during the soldering process, resulting in a higher number of small solder balls precipitating from the surface of the joint. In addition, EPMA showed that Ti NPs adsorbed on the Cu6Sn5 grains, leading to changes in the morphology of the Cu6Sn5 grains and a decrease in the thickness of the IMC layer. The addition of Ti NPs had little effect on the mechanical properties of solder alloys. Excessive Ti NPs will agglomerate, leading to a sharp decrease in the shear strength of the solder joints.

Research on Fe Removal, Regeneration Process, and Mechanical Properties of Mg Alloy AM50A

In recent years, the widespread application of Mg alloy casting and Mg alloy products has generated a large amount of Mg alloy waste. This experiment used a single factor experimental analysis method to study the optimal process for removing Fe from Mg alloy AM50A waste, and developed an efficient Fe removal and regeneration process for Mg alloy AM50A. It was found that the optimal refining temperature for removing Fe ions was 670 °C, the optimal refining (RJ-2) agent mass ratio was 1.5%, and the optimal refining time was 40 min. Regenerated J40-1.5-AM50A Mg alloy was prepared using the best refining process, and its composition and mechanical properties were tested and analyzed. The experimental results show that the composition of the regenerated J40-1.5-AM50A Mg alloy prepared by this method is consistent with AM50A, with an Fe removal rate of 96.2%. The mechanical properties were improved compared to the original AM50A sample, with a maximum tensile strength increase of 1.611 KN and a tensile strength increase of 26.333 MPa. The elongation after fracture is 2.25 times that of the original sample. Research has shown that the RJ-2 refining agent can provide mechanical properties of magnesium alloys during the refining process. By analyzing the composition, XRD, SEM, and EDS of AM50A (Fe) and J40-1.5-AM50A, it was found that the refining process accelerates the removal of Fe in the form of Fe deposition.

Crystal Plasticity Finite Element Analyses on the Formability of AA6061 Aluminum Alloy with Different Ageing Treatments

Different ageing treatments have been developed to achieve targeted properties in aluminum alloys through altering microstructures. However, there is a lack of understanding regarding the effect of ageing treatments on the formability of these alloys. In this study, we employed crystal plasticity finite element (CPFE) modeling, in conjunction with the Marciniak-Kuczynski (M-K) approach, to investigate the effects of ageing treatments on the mechanical properties and formability of AA6061 aluminum alloy. The as-received sheet was in the T6 heat treatment state, which was subjected to artificial ageing and pre-ageing, respectively, to achieve two age-hardened alloys with modified precipitation states. The microstructures and crystallographic textures of the three alloys were measured using the electron backscattering diffraction (EBSD) technique, and uniaxial tensile tests were performed along the rolling direction (RD), transverse direction (TD), and diagonal direction (DD, 45° to the RD) for each alloy. The forming limit curve (FLC) of the as-received alloy was determined using the Nakazima test. The dependence of mechanical strength, tensile ductility, and work-hardening behavior on the ageing treatments was clarified. Then, the tensile test results were utilized to calibrate the modeling parameters used in the CPFE model, whereas the FLC predictability of the developed model was validated with the experimental one. In the formability analysis, the effects of the ageing treatment on the FLC exhibit a notable dependency on loading paths, and the pre-aged alloy exhibits better formability than the other two at the plane strain tension state, thanks to its high work-hardening levels. In addition, the deformed textures along the different loading paths and the effects of the initial texture on the FLC are also discussed.

Improving the Tribological Properties of WE43 and WE54 Magnesium Alloys by Deep Cryogenic Treatment with Precipitation Hardening in Linear Reciprocating Motion.

This paper presents the results of tribological tests on WE43 and WE54 magnesium alloys with rare earth metals performed in linear reciprocating motion for four different material couples (AISI 316-L steel, silicon nitride-Si3N4, WC tungsten carbide, and zirconium dioxide-ZrO2). Additionally, magnesium alloys were subjected to a complex heat treatment consisting of precipitation hardening combined with a deep cryogenic treatment. The study presents the effect of deep cryogenic treatment combined with precipitation hardening on the tribological properties of WE43 and WE54 alloys. Tribological tests revealed the most advantageous results for the magnesium alloy-AISI 316-L steel friction node. For both alloys tested after heat treatment, a nearly 2-fold reduction in specific wear rate has been achieved. Furthermore, microscopic examinations of the wear track areas and wear products were performed, and the wear mechanisms and types of wear products occurring in linear reciprocating friction were determined. Wear measurements were taken using the 3D profilometric method and compared with the results obtained from calculations performed in accordance with ASTM G133 and ASTM D7755, which were modified to improve the accuracy of the calculation results (the number of measured profiles was increased from four to eight). Appropriately selected calculation methods allow for obtaining reliable tribological test results and enabling the verification of both the most advantageous heat treatment variant and material couple, which results in an increase in the durability of the tested alloys.

Group IV topological quantum alloy and the role of short-range order: the case of Ge-rich Ge1–xPbx

Despite the explosion of interest in topological materials over the last decades, their applications remain limited due to challenges in growth and incorporation with today’s microelectronics. As a potential bridge to close this gap, we investigate the group-IV alloy Ge1–xPbx, in the Ge-rich condition using density functional theory and show that relatively low concentrations of Pb (~9.4%) can lead to a topological phase transition. Furthermore, the calculation of the Z2 invariant for both the random alloy and the alloy with short-range order (SRO) indicate that the topological phase of the material can be directly modified by the degree of SRO. These findings are understood in terms of local structural relaxation, which decreases the bandgap in the random alloy. However, in the SRO case, the mutual avoidance of Pb leads to minimal structural relaxation, alleviating strain. Our findings not only highlight the emerging importance of SRO in alloy properties but also indicate the possibility of constructing topological interfaces between materials of identical composition (and nominally identical structure). Moreover, they uncover a viable avenue toward the monolithic integration of quantum materials with today’s semiconductor industry.