Properties Of Alloys Research Articles

Investigating the effect of zirconium dioxide micro and nano particles on the mechanical characteristics of Al-7075 alloy

ABSTRACT The study investigates the influence of zirconium dioxide (ZrO2) particles on the mechanical properties of Al7075 alloy and aims to assess the potential for tailored compositions to meet specific engineering requirements, particularly in aerospace applications. Al7075-ZrO2 composite was fabricated with varying percentages of micro (µ) ZrO2 (1%, 2%, and 3%) and nano ZrO2 (0.17%, 0.34%, and 0.51%) particles using the stir casting technique. Mechanical testing was conducted to evaluate the peak stress, load, and yield strength of the resulting Al7075-ZrO2 composites. Experimental findings reveal that the highest peak stress and load were achieved at 0.51% nano ZrO2 content, indicating a reinforcement effect. Moreover, the composite with 0.34% nano ZrO2 exhibited 59% increased peak stress of 153 MPa and 24% decreased strain 3.7% compared 125 MPa and 4.9% for pure Al7075. Al7075-µZrO2 composite has shown 125 MPa of peak stress and 2.9% maximum strain. These properties highlight the potential of Al7075-ZrO2 composite for applications requiring high resistance to tensile failure. Incorporating nano ZrO2 particles positively impact the load-bearing capacity and strength of Al7075 alloy matrix. Specifically, compositions with tailored ZrO2 content percentages demonstrate the potential for meeting the stringent requirements of aerospace applications.

Effect of Continuous Casting and Heat Treatment Parameters on the Microstructure and Mechanical Properties of Recycled EN AW-2007 Alloy

Effect of Continuous Casting and Heat Treatment Parameters on the Microstructure and Mechanical Properties of Recycled EN AW-2007 Alloy

Enhancement of mechanical and tribological performance of Ti–6Al–4V alloy by laser surface alloying with Inconel 625 and SiC precursor materials

This study focused on producing metal matrix composite (MMC) coatings on Ti–6Al–4V alloy through laser surface alloying using a novel combination of Inconel 625 and SiC precursor materials. Various ratios of alloying powders were examined to evaluate surface properties such as microhardness, wear resistance, and friction coefficient, along with analyzing the phase composition and microstructure of the coatings. The in situ synthesized MMC coatings exhibited the presence of α-Ti, NiTi, NiTi2, and TiC phases. Additionally, Ti5Si3 and α-Ti/Ti5Si3 eutectic structures were observed when the SiC content exceeded 20%. In comparison to the titanium substrate, the MMC coating significantly enhanced microhardness by over threefold and reduced wear by 95%. However, it was crucial to carefully select the appropriate combination of alloying powders to avoid a substantial decrease in friction performance and excessive formation of cracks. Through a comparative analysis of experimental results, the optimal precursor material composition was identified as 85% Inconel 625 and 15% SiC. This study demonstrated the effective utilization of Inconel 625 and SiC alloying materials to enhance the surface properties of titanium alloys, thereby expanding their application in challenging environments.

Predictive Modeling and Analysis of Cu–Be Alloys: Insights into Material Properties and Performance

Cu–Be alloys are renowned for their exceptional mechanical and electrical properties, making them highly sought after for various industrial applications. This study presents a comprehensive approach to predicting the compositions of various types of Cu–Be alloys, integrating a Random Forest Regressor within a machine learning (ML) framework to analyze an extensive dataset of chemical and thermo-mechanical parameters. The research process incorporated data preprocessing, model training and validation, and robust analysis to discern feature significance. Cluster analysis was also conducted to illuminate the data’s intrinsic groupings and to identify underlying metallurgical patterns. The model’s predictive power was confirmed by high R2 values, indicative of its capability to capture and explain the variance in the dataset for both testing (R2 = 0.99375) and training (R2 = 0.99858). Distinct groupings within the alloy data were uncovered, revealing significant correlations between composition, processing conditions, and alloy properties. The findings underscore the potential of ML techniques in advancing the material design and optimization of Cu–Be alloys, providing valuable insights for the field of material science.

Experimental investigation on surface integrity and fatigue performance of Ti60 alloy under ultrasonic impact treatment

The surface integrity and fatigue properties of Ti60 alloy under different ultrasonic impact processes were investigated. Ultrasonic impact treatment (UIT) with various parameters enhanced the surface integrity of the turned specimen. The Ra values of the UIT specimens were all less than 0.380 μm, with the surface stress concentration factor (Kst) values ranging from 1.075 to 1.120. The compressive residual stress values of the UIT specimens were enhanced, leading to the localization of the maximum residual stress (σrsm) in the subsurface. Increases in surface residual stress (σs) values exceeded 21.9 % and σrsm values were improved by more than 74.4 % compared to the turned specimen. The microhardness values showed improvement after UIT, with surface microhardness (HVs) values ranging from 408.5 HV0.025 to 461.6 HV0.025. The orientation of the grains was deflected in UIT specimens, and the depths of the plastic deformation layer (hp) values experienced increases of more than 17 times. The fatigue life (Nf) value of the Comb. U2 with the best surface integrity was approximately 9328.4 % higher than that of turned and about 4362.1 % higher than that of Comb. U1 with the worst surface integrity among the UIT specimens. Observing the fatigue fractures, the crack initiation locations of the UIT specimens were relocated to the subsurface at a distance of more than 150 μm from the surface. A higher fatigue life of the specimen was achieved when there was better surface integrity and when the fatigue crack source was located further away from the surface. The crack source in the UIT specimen exhibited a large and irregular shape, and there were numerous small, evenly distributed dimples and a limited number of cleavage planes in fatigue instantaneous fracture region. Additionally, it was found that the subsurface fatigue life prediction model demonstrates superior accuracy for shorter fatigue life.

Investigation of the structural, Electronic and magnetic properties of Mn2PdSn Heusler alloy under hydrostatic pressure

The pressure effect on the structural, electronic and magnetic properties of Mn2PdSn Heusler alloy was investigated by the first-principles full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT). The exchange and correlation function has been chosen using generalized gradient approximation (GGA) within the parameterization of Perdew-burke-ernzerhof. The lattice constant, electronic density of state (DOS), and magnetic properties such as total magnetic moment were obtained under pressure. It was determined that the calculated lattice parameters are in good agreement with the literature. The Mn2PdSn is stable in the Hg2CuTi-type structure. Furthermore, we expect an extraordinary occurrence of pressure-induced metallic ferrimagnetism to half-metallic ferromagnetism transition in the cubic phase of Mn2PdSn alloy at hydrostatic pressures of 10 GPa.

First-principles study of the structure, magnetism, and electronic properties of the all-Heusler alloy Co2MnGe/CoTiMnGe(100) heterojunction

Based on first-principles calculations in the density functional theory, we systematically investigated the possible interface structure, magnetism, and electronic properties of the all-Heusler alloy Co2MnGe/CoTiMnGe(100) heterojunction. The calculation indicated that the Co2MnGe Heusler alloy is a half-metal with a magnetic moment of 4.97 μB. CoTiMnGe is a narrow-band gap semiconductor and may act as an ultra-sensitive photocatalyst. We cannot find an “ideal” spin-polarization of 100% in CoCo termination and MnGe termination. Due to the interface interaction, the direct magnetic hybridization or indirect RKKY exchange will be weakened, leading to an increase in the atomic magnetic moment of the interfacial layer. For eight possible heterojunction structures, the half-metallic gaps in the Co2MnGe bulk have been destroyed by the inevitable interface states. The spin-polarization value of 94.31% in the CoCo-TiGe-B heterojunction revealed that it is the most stable structure. It is feasible to search for high-performance magnetic tunnel junction by artificially constructing suitable all-Heusler alloy heterojunctions.

Machine learning classification approach for predicting tensile strength in aluminium alloy during friction stir welding

AbstractThe machine learning (ML) methodology is receiving significant attention as a promising approach for addressing and modeling manufacturing challenges. This research designed an ML framework to forecast the tensile strength of aluminium alloys produced using friction stir welding (FSW). The dataset comprising 213 samples of aluminium alloy sourced from peer-reviewed literature was used. A range of ML algorithms such as decision tree, random forest, adaptive boosting classifier (ABC), k-nearest neighbors, gaussian naive Bayes classifier, and support vector machines were applied to the dataset. The findings revealed that the ABC algorithm attained the highest accuracy, reaching 81.6% among the models tested. This study highlights the effectiveness of ML methodologies in predicting the tensile properties of FSW-manufactured aluminium alloys, thus driving progress in the field of welding and joining.

Machine learning classification approach for predicting tensile strength in aluminium alloy during friction stir welding

AbstractThe machine learning (ML) methodology is receiving significant attention as a promising approach for addressing and modeling manufacturing challenges. This research designed an ML framework to forecast the tensile strength of aluminium alloys produced using friction stir welding (FSW). The dataset comprising 213 samples of aluminium alloy sourced from peer-reviewed literature was used. A range of ML algorithms such as decision tree, random forest, adaptive boosting classifier (ABC), k-nearest neighbors, gaussian naive Bayes classifier, and support vector machines were applied to the dataset. The findings revealed that the ABC algorithm attained the highest accuracy, reaching 81.6% among the models tested. This study highlights the effectiveness of ML methodologies in predicting the tensile properties of FSW-manufactured aluminium alloys, thus driving progress in the field of welding and joining.

Effect of the structure and volume fraction of nanophase on the mechanical properties of (FeNi)86B14 amorphous nanocrystalline alloys

The influence of precipitated nanophases on the mechanical properties of Fe-based amorphous nanocrystalline alloys is an urgent issue to be explored. Two amorphous nanocrystalline alloys, i.e., (Fe0.9Ni0.1)86B14 and (Fe0.7Ni0.3)86B14 containing nanophase of the body-centered cubic and face-centered cubic structures, respectively, were selected to investigate the effect of the structure and volume fraction of nanophase on their mechanical properties. The results of nanoindentation experiments and the calculation of the volume and size of the shear transition zone reveal that the two alloys show different mechanical properties. When the volume fraction of the nanophase in (Fe0.9Ni0.1)86B14 is larger than 50%, the elastic modulus is increased suddenly and the volume and size of the shear transition zone is decreased dramatically, while no dramatic change occurs in (Fe0.7Ni0.3)86B14. Moreover, it was found by using molecular dynamics simulations that the main reason for these abnormal mechanical properties is the change of cluster type in the system due to the incorporation of nanophases with different structures.

Effect of the structure and volume fraction of nanophase on the mechanical properties of (FeNi)86B14 amorphous nanocrystalline alloys

The influence of precipitated nanophases on the mechanical properties of Fe-based amorphous nanocrystalline alloys is an urgent issue to be explored. Two amorphous nanocrystalline alloys, i.e., (Fe0.9Ni0.1)86B14 and (Fe0.7Ni0.3)86B14 containing nanophase of the body-centered cubic and face-centered cubic structures, respectively, were selected to investigate the effect of the structure and volume fraction of nanophase on their mechanical properties. The results of nanoindentation experiments and the calculation of the volume and size of the shear transition zone reveal that the two alloys show different mechanical properties. When the volume fraction of the nanophase in (Fe0.9Ni0.1)86B14 is larger than 50%, the elastic modulus is increased suddenly and the volume and size of the shear transition zone is decreased dramatically, while no dramatic change occurs in (Fe0.7Ni0.3)86B14. Moreover, it was found by using molecular dynamics simulations that the main reason for these abnormal mechanical properties is the change of cluster type in the system due to the incorporation of nanophases with different structures.

Effects of Sc–Er Rare Earth on Solidification Microstructure and Mechanical Properties of A360 Alloy

Effects of Sc–Er Rare Earth on Solidification Microstructure and Mechanical Properties of A360 Alloy

Effect of Heterogeneous Deformation on Microstructure and Microtexture Evolution of Ti‐6Al‐4V Alloy during Multidirectional Isothermal Forging

The heterogeneous deformation of Ti‐6Al‐4V alloy during multidirectional isothermal forging and its effect on microstructure, microtexture, and related mechanical properties are investigated here. It is found that lowering the deformation temperature, combined with increasing the number of forging times, accelerates the grain refinement and recrystallization process in the as‐received billet, especially in the surface section rather than the inner of the billet. Finally, a heterogeneous lamellar structure is formed after annealing the billet with a fourth step of forging. The heterogeneous lamella structure enables a better synergy of strength and ductility when compared to its equiaxed counterpart, achieving a high tensile strength of 1194 MPa and an elongation of 13.1%. During the deformation, a high proportion of back stress to total flow stress, ranging from 64–67%, denotes that back stress strengthening is one of the main reasons for the better synergy of strength and ductility. This study guides a low‐cost and convenient way for the regulation of microstructure and mechanical properties of titanium alloy with good performance.

Relevant Aspects in the Mechanical and Aging Degradation of NiTi Alloy with R-Phase in Endodontic Files.

One of the most important challenges in endodontics is to have files that have excellent flexibility, toughness, and high fatigue life. Superelastic NiTi alloys have been a breakthrough and the new R-phase NiTi alloys promise to further optimize the good properties of NiTi alloys. In this work, two austenitic phase endodontic files with superelastic properties (Protaper and F6) and two austenitic phase files with the R-phase (M-wire and Reciproc) have been studied. The transformation temperatures were studied by calorimetry. Molds reproducing root canals at different angles (30, 45, and 70°) were obtained with cooling and loads simulating those used in the clinic. Mechanical cycles of different files were realized to fracture. Transformation temperatures were determined at different number of cycles. The different files were heat treated at 300 and 500 °C as the aging process, and the transformation temperatures were also determined. Scanning and transmission electron microscopy was used to observe the fractography and precipitates of the files. The results show that files with the R-phase have higher fracture cycles than files with only the austenitic phase. The fracture cycles depend on the angle of insertion in the root canal, with the angle of 70° being the one with the lowest fracture cycles in all cases. The R-Phase transformation increases the energy absorbed by the NiTi to produce the austenitic to R-phase and to produce the martensitic transformation causing the increase in the fracture cycles. Mechanical cycling leads to significant increases in the transformation temperatures Ms and Af as well as Rs and Rf. No changes in the transformation temperatures were observed for aging at 300 °C, but the appearance of Ni4Ti3 precipitates was observed in the aging treatments to the Nickel-rich files that correspond to those with the R transition. These results should be considered by endodontists to optimize the type of files for clinical therapy.

Relevant Aspects in the Mechanical and Aging Degradation of NiTi Alloy with R-Phase in Endodontic Files

One of the most important challenges in endodontics is to have files that have excellent flexibility, toughness, and high fatigue life. Superelastic NiTi alloys have been a breakthrough and the new R-phase NiTi alloys promise to further optimize the good properties of NiTi alloys. In this work, two austenitic phase endodontic files with superelastic properties (Protaper and F6) and two austenitic phase files with the R-phase (M-wire and Reciproc) have been studied. The transformation temperatures were studied by calorimetry. Molds reproducing root canals at different angles (30, 45, and 70°) were obtained with cooling and loads simulating those used in the clinic. Mechanical cycles of different files were realized to fracture. Transformation temperatures were determined at different number of cycles. The different files were heat treated at 300 and 500 °C as the aging process, and the transformation temperatures were also determined. Scanning and transmission electron microscopy was used to observe the fractography and precipitates of the files. The results show that files with the R-phase have higher fracture cycles than files with only the austenitic phase. The fracture cycles depend on the angle of insertion in the root canal, with the angle of 70° being the one with the lowest fracture cycles in all cases. The R-Phase transformation increases the energy absorbed by the NiTi to produce the austenitic to R-phase and to produce the martensitic transformation causing the increase in the fracture cycles. Mechanical cycling leads to significant increases in the transformation temperatures Ms and Af as well as Rs and Rf. No changes in the transformation temperatures were observed for aging at 300 °C, but the appearance of Ni4Ti3 precipitates was observed in the aging treatments to the Nickel-rich files that correspond to those with the R transition. These results should be considered by endodontists to optimize the type of files for clinical therapy.

Achieving back-stress strengthening at high temperature via heterogeneous distribution of nano TiBw in titanium alloy by electron beam powder bed fusion

Back-stress strengthening has been proven to be an effective strategy in breaking the room temperature strength–ductility dilemma in hetero-structural metals matrix composite materials (MMC). However, back-stress is difficult to achieve at high temperature because of grain boundary softening, grain boundary sliding, dislocation annihilation and grain rotation. Here, back-stress strengthening is exploited to improve the high temperature tensile properties of Ti-6Al-4 V (TC4) alloy by precipitating a heterogeneous distribution of nano TiB whiskers (TiBw). In this work, the rapid solidification associated with electron beam powder bed fusion (EB-PBF) generates heterogeneous in-situ nano TiBw at both grain boundaries and grain interiors. The nano-TiBw on the grain boundaries (GB nano-TiBw) not only refines the grains but can also pin the grain boundaries. The intragranular nano TiBw (IG nano-TiBw) significantly reduces the dislocation mean free path, inhibit dislocation movement, and dramatically enhances the dislocation storage density. Meanwhile, specimens are strengthened by high-density < a + c > dislocations induced by the precipitated nano TiBw. The heterogeneous distribution of nano TiBw achieved a 50 °C increase in the service temperature of TC4 alloy while also increasing stability. This strategy provides a new perspective for further improving the high-temperature mechanical properties of titanium alloys.

Microstructure and properties of Zircaloy-4 alloy under low-temperature diffusion bonding with a Ni-plated surface

Zircaloy-4, which is used as a structural material for nuclear cladding, requires precise bonding at low temperature in nuclear power applications. We achieved this using diffusion bonding with Ni plating on the surface of Zircaloy-4. We evaluated the performance of joints at temperatures between 650 and 780 °C. At 650 °C, the joint was successfully bonded. The joint exhibited a maximum shear strength of 207 MPa at 780 °C, which was twice as high as that produced by direct diffusion bonding at 700 °C under the same parameters. The interface was analyzed by using a combination of SEM and TEM to identify the presence of multilayered intermetallic compound layers in the joints. We investigated the mechanism of interface generation and determined the sequence of phase formation by Gibbs free energy calculations to be NiZr, Ni10Zr7, NiZr2, Ni7Zr2, and Ni3Zr. Through X-ray diffraction and cross-section elemental analysis of the fractures, we observed that, at lower temperatures, the joint fracture tended to occur in the Ni layer, whereas at higher temperatures, it occurred between Ni7Zr2 and Ni3Zr. The utilization of diffusion welding with Ni plating applied to the surface of Zircaloy-4 reduces the joining temperature and enhances the properties of the joint.

Improvement of Mechanical and Wear Properties of Tungsten Heavy Alloy Using Two-Stage Sintering and Carburizing Processes

Improvement of Mechanical and Wear Properties of Tungsten Heavy Alloy Using Two-Stage Sintering and Carburizing Processes

Formation of a protective oxides-nitrides compound layer with enhanced wear properties, corrosion resistance, and cytocompatibility on novel Ti-Zr-Nb-Ta-Mo multi-principal element alloy

The insufficient surface properties of multi-principal element alloys (MPEAs) hinder their potential biomedical applications. Here, a facile thermal oxidation plus nitridation treatment is conducted to fabricate a protective layer on a novel Ti-Zr-Nb-Ta-Mo MPEA. The total surface layer of NT5-ON consists of a top compound layer, including TiO2, TiN, TiON, ZrO2, and ZrN, and an underneath N-diffusion zone, leading to an exceptionally high wear performance. Also, electrochemical testing and in-vitro evaluations demonstrated enhanced corrosion resistance and cytocompatibility of NT5-ON. As a result, thermal oxidation plus nitridation treatment is an effective technique for designing high-performance hip implant materials.

Investigation of bio-corrosion behavior, structural and thermal properties of Ni20Ti50Sn30 high-temperature shape memory alloy

Investigation of bio-corrosion behavior, structural and thermal properties of Ni20Ti50Sn30 high-temperature shape memory alloy