Addition Of Ti Research Articles

INVESTIGATIONS ON MECHANICAL, WEAR AND MACHINING BEHAVIOR OF TITANIUM-REINFORCED AlMg0.5Si COMPOSITES

AlMg0.5Si (AA6063) as a base matrix composite with different weight percentages of Titanium (Ti) has been synthesized by the stir casting method. Objective of this research is to investigate the effect of Ti addition on AA6063 to produce aluminium matrix composites (AMCs). AA6063, AA6063/4%-Ti, AA6063/8%-Ti, and AA6063/12%-Ti are different volume fractions. The Scanning electron microscope (SEM) analysis is used to examine the modified grain refinement and worn surface on fabricated AMCs. The evenly distributed structure was attained on the processed AA6063/Ti combinations. The mechanical properties of processed composites were investigated with the following experimental tests such as tensile strength, impact strength, micro hardness, compressive, and flexural strength. The entire mechanical properties of fabricated AMCs were enhanced with increasing Ti reinforcement particles. The CNC drilling of AA6063/Ti composites was machined by spindle speed, feed and depth of cut. The gray relational analysis (GRA) was used to carry out the optimal machining parameters with their responses such as material removal rate and surface roughness. From the analysis of ANOVA, spindle speed parameter achieved most influencing parameters.

Novel magnesium matrix hybrid composites manufactured through powder metallurgy technique

In the present study, novel magnesium matrix hybrid composites have been developed through the addition of titanium and nickel micro particulates using the hot pressing technique which is one of the powder metallurgy methods. Titanium and nickel elements were first-time used in combination as reinforcing materials in the manufacture of hybrid composites. A clean interface was obtained free from porosity, oxide and unwanted secondary phases between the matrix and reinforcement in all produced samples. In addition to the matrix and reinforcement phases, the Mg2Ni phase was also observed in the microstructural characterizations. The existence of this phase was confirmed through XRD analyses, its peak intensity increased with the increasing amount of reinforcement. While the addition of Ti and Ni provided a mean of 33 % and 83 % improvement in the yield strength and compressive strength of pure magnesium at room temperature, respectively, they did not cause a serious decrease in ductility values compared to those of ceramic reinforcement materials. The yield and compressive strengths of hybrid composites were found to be greater than those of the reference sample at all test temperatures. The mechanical properties such as yield strength, compressive strength and ductility together with low densities have shown that produced hybrid materials constitute an important alternative to traditional materials such as iron, steel and even aluminum frequently used in the manufacture of automobile components.

Influence of Ti addition on the precipitation behavior and mechanical properties of Ni-7.9Cr-5.9W-22.2Mo superalloy

The Ni-7.9Cr-5.9W-22.2Mo-1.4Ti superalloy based on Ni-8Cr-6W-22.5Mo (the Haynes 244 alloy) was prepared to investigate the effect of Ti addition on the precipitation behavior and mechanical properties. The results indicate that the addition of Ti can facilitate the formation of C11b and D022 superlattice phases simultaneously after age-treated at 650 °C for 240 h. The yield strength is significantly improved to 1645 MPa compared with Ni-8Cr-6 W-22.5Mo with only the formation of C11b and a yield strength of 1297 MPa. The excellent strengthening effect of C11b and D022 superlattice phases are attributed to both order strengthening and coherency strengthening, and their calculated contributions to strengthening are 148 MPa and 439 MPa for D022 and 83 MPa and 208 MPa for and C11b, respectively. Together with solid-solution strengthening and grain refinement strengthening, the theoretically calculated yield strength matches well with the experimental results. In addition, the deformation mode changes from deformation slip to strain-induced twinning after the Ti addition.

Thermal properties of spark plasma sintered Inconel 625 modified by titanium zirconium mixed carbide

Nickel-based superalloys are an important group of advanced engineering materials used for high-temperature and/or corrosive environments. Lately, in order to improve their mechanical properties, carbide reinforcement is added to a metal matrix, creating composites of improved hardness, shear resistance, or tensile resistance. In order to preserve the wide applicability of those materials, thermal properties, and corrosion resistance must also be evaluated. Presented research evaluated the thermal properties of Inconel 625—(Ti,Zr)C0.85 composites obtained at 1000 °C by spark plasma sintering process. Sinters containing 5–20 mass% of carbide phases were initially characterized in terms of their density, phase composition, and microstructure. A thorough examination of their thermal properties included: dilatometry, laser flash analysis, and differential scanning calorimetry. Conducted experiments revealed that a growing amount of carbide reinforcement decreased the thermal diffusivity and conductivity of samples. Other materials had a nonlinear correlation with that parameter. Performed analysis allowed to make an initial evaluation of oxidation resistance at 800 °C. It was shown that above 5 mass% addition of (Ti,Zr)C0.85 there is a considerable mass gain change shown by samples during the first hour of oxidation before passive layers were created. Suitable chemical reactions were predicted in order to describe the oxidation process of obtained composites.

Exceptional enhancement of mechanical properties in high-entropy alloys via thermodynamically guided local chemical ordering

Understanding the local chemical ordering propensity in random solid solutions, and tailoring its strength, can guide the design and discovery of complex, paradigm-shifting multicomponent alloys. First, we present a simple thermodynamic framework, based solely on binary enthalpies of mixing, to select optimal alloying elements to control the nature and extent of chemical ordering in high-entropy alloys (HEAs). Next, we couple high-resolution electron microscopy, atom probe tomography, hybrid Monte-Carlo, special quasirandom structures, and density functional theory calculations to demonstrate how controlled additions of Al and Ti and subsequent annealing drive chemical ordering in nearly random equiatomic face-centered cubic CoFeNi solid solution. We establish that short-range ordered domains, the precursors of long-range ordered precipitates, inform mechanical properties. Specifically, a progressively increasing local order boosts the tensile yield strengths of the parent CoFeNi alloy by a factor of four while also substantially improving ductility, which breaks the so-called strength-ductility paradox. Finally, we validate the generality of our approach by predicting and demonstrating that controlled additions of Al, which has large negative enthalpies of mixing with the constituent elements of another nearly random body-centered cubic refractory NbTaTi HEA, also introduces chemical ordering and enhances mechanical properties.

Study of the Mechanisms of Radiation Softening and Swelling upon Irradiation of TiTaNbV Alloys with He2+ Ions with an Energy of 40 keV.

This paper presents simulation results of the ionization losses of incident He2+ ions with an energy of 40 keV during the passage of incident ions in the near-surface layer of alloys based on TiTaNbV with a variation of alloy components. For comparison, data on the ionization losses of incident He2+ ions in pure niobium, followed by the addition of vanadium, tantalum, and titanium to the alloy in equal stoichiometric proportions, are presented. With the use of indentation methods, the dependences of the change in the strength properties of the near-surface layer of alloys were determined. It was established that the addition of Ti to the composition of the alloy leads to an increase in resistance to crack resistance under high-dose irradiation, as well as a decrease in the degree of swelling of the near-surface layer. During tests on the thermal stability of irradiated samples, it was found that swelling and degradation of the near-surface layer of pure niobium affects the rate of oxidation and subsequent degradation, while for high-entropy alloys, an increase in the number of alloy components leads to an increase in resistance to destruction.

Synergistic optimization of mechanical and tribological properties of TiC modified copper-graphite composites by direct current in-situ sintering

The application of Cu-graphite composites in the field of friction materials is limited by the poor wettability between Cu and graphite and weakened mechanical properties. In this work, in-situ TiC layers were generated by interfacial resistance sintering with direct current to manipulate the interfacial bonding of the composites and enhance their comprehensive properties. The Ti added to the composites would react with graphite at the interface to generate TiC layers and form strong Cu–TiC-graphite interfaces due to interfacial reactions. When the added Ti content is 6 wt%, the composite demonstrates the most excellent mechanical properties and tribological characteristics, i.e., yield strength (168 MPa) and wear rate (2.7 × 10−10 m2/N) are 93.1% higher and 29.7% lower than those of the Cu-graphite composite without Ti addition, respectively. The dense TiC layer induces the strengthening of the Cu matrix and serves as the reinforcing phase to optimize the interfacial bonding and stress transfer, which not only greatly enhances the mechanical properties of the composite but also enables the composite to take full advantage of the hard TiC and graphite phases to obtain stable friction coefficient and low wear rate. This work provides a simpler technique to prepare modified Cu-graphite composites with excellent performance and contributes to the in-depth understanding of the enhancement mechanism of hard ceramic layers on the mechanical and tribological properties of composites.

Microstructure and oxidation resistance of Ti modified Si-Mo coating on Nb-Si based ultrahigh temperature alloy

Ti modified Si-Mo coatings have been successfully prepared on Nb-Si based ultrahigh temperature alloy by slurry sintering method. The results show that the addition of Ti as well as its content has an obvious influence on the density, grain size and oxidation resistance of the coatings. The 5 at% Ti modified coating possesses the best oxidation protection performance with a multi-layered structure consisting of a C11b MoSi2/C40 (Mo,Ti)Si2 outer layer and a dense (Ti,Nb)5Si4/(Nb,X)5Si3 inner layer. After oxidation, the formation of SiO2 and TiO2 can quickly seal the holes in the coating and form a dense SiO2/TiO2 scale.

Effect of Ti Addition on Microstructure Evolution and Mechanical Properties of Al18Co13Cr10Fe14Ni45 Eutectic High-Entropy Alloys

Effect of Ti Addition on Microstructure Evolution and Mechanical Properties of Al18Co13Cr10Fe14Ni45 Eutectic High-Entropy Alloys

Effect of alloying elements (Mn, Ti, and Mo) on the corrosion behavior of FeCoNiCr-based high entropy alloy in supercritical water

The effect of alloying elements, Mn, Ti, and Mo, on the corrosion behavior of FeCoNiCr-based high entropy alloy (HEA) in supercritical water was investigated. The corrosion resistance of the HEA was enhanced by adding Mo while reduced with the addition of Ti and Mn. The segregation of Ti and Mo resulted in the formation of oxide films that were both structurally and chemically heterogeneous. Grain boundaries accelerated the diffusion rate of Mn, leading to the formation of MnCr2O4 oxide scales decorated with Mn2O3 particles. In addition, the governing mechanisms of alloying elements on the corrosion behavior of HEAs were also discussed.

Effect of Ti additions on microstructure and mechanical properties of Cu–Cr–Zr alloy

Ti additions in Cu–Cr–Zr alloys are useful for achieving high mechanical properties. In this work, the influence of Ti contents (0.25 wt%, 0.6 wt%, and 1.02 wt%) on the microstructure, mechanical, and electrical properties of Cu–Cr–Zr alloys has been investigated experimentally, along with thermodynamic and kinetic calculations. The electrical conductivity decreased but the hardness/strength increased with increasing Ti content. The lower electrical conductivity is due to increased electron scattering through the solution of more Ti atoms in the Cu matrix. As for the higher hardness/strength, it is mainly owing to higher dislocation density and finer FCC-Cr precipitates. Furthermore, a model considering the size distributions of precipitates is adopted to calculate precipitation strengthening quantitatively. The calculated yield strengths are consistent with the experimental ones for the alloys. The thermodynamic and kinetic calculations reveal that increasing Ti content can facilitate the nucleation of FCC-Cr but enhance its activation energy, hence hindering the growth process. The present work study can provide an effective strategy for producing copper alloys with expected performance.

Sn Diffusion Behavior and Microstructure in Nb<sub>3</sub>Sn Wires with Third Elemental Addition

Element addition plays an important role in the improvement of the physical properties of the Nb3Sn phase itself and of growth kinetics in the Nb3Sn diffusion reaction process. This paper first reviews the fundamental reaction behavior between Nb and Sn in the presence of Cu, which is the integral element for the thick Nb3Sn layer formation at a low temperature reaction, and interprets it in view of Sn chemical potential. Then the paper reviews several advanced element additions to realize breakthrough grain refinement, touching on their grain refinement mechanism. Subsequently, the recent topic of Ti and Ta addition is examined, followed by the addition of unique elements that bring functional enhancement such as mechanical strengthening of the wire.

A crack-free Ti-modified Al-Cu alloy processed by in-situ alloying laser powder bed fusion: Tribological behaviors and mechanical properties

High strength Al-Cu alloys are of great interest for processing using additive manufacturing for aerospace applications. In this study, a Ti-modified Al-Cu alloy was successfully processed by in-situ alloying laser powder bed fusion (LPBF). The relationship between the volumetric energy density (VED) and the densification of a Ti-modified and unmodified Al-Cu alloy was investigated. The results showed that a high-density, crack-free Al-Cu alloy can be achieved with the addition of Ti. Hot cracks occurred along the coarse columnar grains in the unmodified Al-Cu alloy due to the severe stress concentrations arising during the LPBF process. The elimination of hot cracks was attributed to the decrease of grain size and the change of grain morphology from columnar to equiaxed with the Ti addition. The tensile properties of the Ti-modified Al-Cu alloy were significantly improved with a yield strength of 200 MPa, an ultimate strength of 289 MPa, and an elongation to failure of 8 %. The strengthening mechanisms including grain refinement strengthening, solid solution strengthening and second phase strengthening were quantified and the fracture mechanism was discussed. The tribological results showed that a low wear rate of 3.03 × 10−4 mm3 N−1 m−1 was achieved in the alloy with Ti modification, while unmodified alloy showed a poor wear resistance. The study demonstrates a novel method to develop advanced Al-Cu alloy with high density, strength and tribological resistance by in-situ alloying LPBF.

An experimental and computational design low-modulus (HfNbTa)1-xTix multiprinciple elemental alloys with super formability for biomedical applications

Stress shielding at the implant-bone interface is the main causes of failure in orthopedic implant surgery, which is induced by the modulus mismatch between implants and bones. Reducing the Young's modulus of biomedical alloys is beneficial to alleviate the stress shielding effect. Recently, biomedical multiprinciple elemental (Bio-MPEAs) have aroused widespread concerns due to their low modulus, high strength, and superior biocompatibility. In this work, a series of (HfNbTa)1-xTix alloys are designed to investigate the effects of Ti content on the structural and mechanical properties of Bio-MPEAs. The obtained results reveal that the designed alloys have a single-phase body-centered cubic (BCC) structure, and exhibit ambient ductility with a tensile elongation >12% and cold-rolling thickness reduction >86%. Ti addition helps to reduce the Young's modulus of Bio-MPEAs. Their super formability stems from the movability of <1 1 1>/2-type dislocations. Solid solution strengthening is the major strengthening mechanism of the alloys. Local lattice distortion plays a key role in solid solution strengthening, which is induced by atomic size mismatch and electronegativity difference of multiple elements. This work not only highlights the positive role of Ti addition for designing low-modulus Bio-MEAs, but also clarifies the physical mechanisms of solid solution strengthening and lattice distortion.

Microstructural Evolution of a High-Strength Zr-Ti-Modified 2139 Aluminum Alloy for Laser Powder Bed Fusion

The demand for high-performance aluminum components drives research into the design of novel alloys that can be processed by laser-based additive manufacturing. In recent years, the addition of grain refiners proved to be an effective strategy to reduce the hot-cracking of high-strength Al alloys. In this study, the solidification and aging behavior of an Al2139 alloy doped with additions of Zr and Ti for L-PBF was investigated. These elements favored the formation of a fine-grained structure free of cracks. The formation of Al3(Zr,Ti) inoculants was predicted by Scheil simulations and observed as cuboidal particles in the center of α-Al grains. The microstructure of the as-built material featured fine and fully equiaxed grains, which appeared comparatively finer at the edge (300–600 nm) and coarser (0.8–2.0 μm) at the center of the molten pools. In both cases, there was evidence of Cu and Mg micro-segregations at the grain boundaries. The microhardness of 109.7 HV0.5 in the as-built state was increased to 186.1 HV0.5 after optimized T4 heat treatment, responsible for the precipitation of many rod-shaped Zr- and Ti-based second phases and quasi-spherical Cu-, Mn-, and Fe-rich particles. Prolonged exposure carried out to simulate high-temperature service caused a drop in microhardness and marked modification of the microstructure, evidenced by the rearrangement and subsequent spheroidization of Cu- and Mg-rich particles at the grain boundaries.

Atomic behavior of Ti in A15 Nb3Sn and its effects on diffusional growth of Nb3Sn layer

Atomic details of the dramatic increase in the diffusional growth rate of A15 Nb3Sn superconducting compound with Ti addition have been investigated using atomistic simulations and experimental observations. Ti atoms preferentially locate at Nb sites in the Nb3Sn bulk while they do not affect the volume diffusion of Sn significantly. In addition, Ti is predicted to segregate on Nb3Sn grain boundaries, inducing the segregation of Sn, but cannot enhance the grain boundary diffusion of Sn enough to explain the dramatic increase in the growth rate of the Nb3Sn layer. On the other hand, grain refinement is observed when Ti is added, which is expected to substantially promote the effective diffusion of Sn. Consequently, grain refinement due to the grain boundary segregation of Ti is revealed as the most important mechanism underlying the alloying effect of Ti. A basic understanding of the atomic behavior of alloying elements in Nb3Sn and clarified alloying effects on the diffusional growth of Nb3Sn compounds will contribute to further investigation of optimal alloying strategies.

Investigation of Microstructure and Mechanical Properties of AlSi7Mg0.3Cu0.5 Alloy with Addition of Zr, Ti and Sr

The main objective of this paper is to investigate the effect of Zr and its synergistic effect together with the addition of an inoculant (Ti) and a modifier (Sr) in terms of structural analysis and mechanical characteristics of AlSi7Mg0.3Cu0.5 alloy. In accordance with the objectives of the paper, in the experimental part, eight material variants were cast by the investment casting method. The presence of Zr in the experimental alloys was manifested by the crystallization of phases with different chemical compositions mainly (AlSi)3(TiZr) and (AlSi)2(TiZr). The graded addition of Ti in the alloys resulted in a higher number of nucleation grains of Zr-rich phases, and alloys with a combination of Zr and Sr were characterized by the formation of (AlSi)2(TiZr) phases. Various types of precipitates based on Zr (Al3(ZrTi)) and Cu (Al2Cu) were observed in the substructure of the alloys. The addition of Zr and its synergistic effect with Ti and Sr led to an increase in the conventional yield strength, hardness and partly tensile strength with reduced elongation of the experimental alloys.

Unique dislocation loops distribution of AlCrFeNiTix eutectic high-entropy alloys under high-temperature ion irradiation

Eutectic high-entropy alloys (EHEAs) have drawn great attention due to their excellent high-temperature mechanical properties. A group of EHEAs AlCrFeNiTix with different titanium contents was irradiated with 3 MeV Fe11+ ions at 500 °C with fluences of 9.1 × 1014 and 4.55 × 1015 ions/cm2. The disordered body-centered-cubic (BCC, A2) exhibited smaller-sized dislocation loops than those of ordered BCC (B2) based on Transmission electron microscopy (TEM) analysis. The type of loops found in AlCrFeNi alloy were<100>and 1/2<111>. The fraction of 1/2<111>was higher, indicating the excellent irradiation resistance of EHEAs. Small size and large density of dislocation loops formed after the addition of Ti. Phase boundaries in the alloys could effectively decrease the density and size of dislocation loops because of defects annihilation at phase boundaries. In combination with density function theory (DFT) results. B2 phase exhibited better energy landscape advantage in the Ti accommodating, and the MSD results indicated that the lattice distortion effect caused by Ti entering B2 phase was more obvious than A2 according to the density function theory (DFT) results. Our research exhibited a beneficial scheme for solid solution strengthening of elements in EHEAs, and provided an insight into the suppression of dislocation loops under irradiation.

Effects of titanium addition on austenite grain size and mechanical properties of high manganese steel

Manganese steels have been widely used in industries due to their good wear resistance, high work hardening ability, and high toughness and ductility. This research investigated the effect of modification, i.e., FeTi and Mischmetal, on the grain size and mechanical properties of the high manganese steel (13–15 wt.%). The alloys are modified at different temperatures of 1500, 1550, and 1600 o. The modified alloys were heat-treated after solidification by a two-step process. The grain size, chemical composition, and phase formation of the heat-treated steel were characterized by Optical Microscopy, X-ray Diffractometry, and Energy-Dispersive X-ray Spectroscopy. The mechanical properties of the steel, such as Brinell hardness, tensile strength, and toughness, were measured. As a result, the grain size of the heat-treated alloys is smaller compared to that of un-modified alloys and decreases with the increase in modification amount. The addition of Ti reduced C in the austenite phase by forming very stable carbides, TiC. Maximum tensile strength of 780 MPa was achieved with the addition of 0.1 wt.% Ti, while maximum fracture toughness was 140 J/cm2 at 0.05 wt.% Ti.

Impact of Ti Doping on the Microstructure and Mechanical Properties of CoCrFeMoNi High-Entropy Alloy

The design principle of high-entropy alloys is to mix many chemical elements in equal or nearly equal proportions to create new alloys with unique and special properties such as high strength, ductility and corrosion resistance. Some properties of high-entropy alloys can be adjusted via introducing new doping elements, which are selected according to working conditions. The high-entropy alloy CoCrFeMoNi was examined to determine the impact of Ti doping on its micro-structure, microhardness and elastic modulus. Microstructure analysis revealed a core structure consisting of both face-centered cubic (FCC) and body-centered cubic (BCC) phases, along with the formation of a Laves phase. The addition of Ti made the alloy grains finer and reduced the Mo concentration difference between the interdendritic and dendritic regions. As a result of Ti doping, the microhardness of the alloy increased from 369 HV 0.2 to 451 HV 0.2. Ti doping produced a doubling of the breaking strength value, although no significant changes were observed in the elastic modulus of the CoCrFeMoNi alloy.