scholarly journals Generation of Microstructural Gradients for Improved Mechanical Properties via Thermo-Hydrogen Treatment of the Metastable Beta Titanium Alloys Beta CTM and Ti 10V-2Fe-3Al

2020 ◽  
Vol 321 ◽  
pp. 12017
Author(s):  
Christopher David Schmidt ◽  
Vitali Macin ◽  
Peter Schmidt ◽  
Hans-Jürgen Christ
Keyword(s):  
Hydrogen Diffusion ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Kinetic Temperature ◽  
Hydrogen Treatment ◽  
Resource Saving ◽  
Alloy Matrix ◽  
Ti Alloys ◽  
Conventional Heat Treatment ◽  
Localized Plastic Deformation

Structural components must be lightweight and produced resource-saving while still fulfil the increasing durability and reliability requirements. One approach to fulfil these requests is a temporary hydrogen charging of Ti-alloys, which generates lattice distortion and hydrides. The volume difference between hydride precipitates and the alloy matrix results in localized plastic deformation. This triggers recrystallization and enables a finer microstructure as attainable by a conventional heat treatment. The study aims at an elaboration of a thermo-hydrogen treatment that establishes a change in grain size and/or an alteration in distribution and morphology of strengthening secondary α precipitates as a function of the distance to surface (microstructural gradient). The gradient is based on a gradient of the hydride volume fraction. Generally, THT design requires kinetic (temperature dependency of the hydrogen diffusion coefficient DH) in addition to thermodynamic (H/β-Ti-alloy interaction) data, which has been obtained for Ti 3Al-8V-6Cr-4Mo-4Zr and Ti 10V-2Fe-3Al. Subsequent to a solution treatment the variation of hydrogenation time and temperature is operated to establish comparably slight microstructural gradients on these materials. For further investigations it is concluded that materials with less alloying elements ((α+β)-Ti-alloys (e.g.,Ti 6Al-4V)) than these β-Ti-alloys can satisfy the requirements to generate steeper microstructural gradients even better.

Influence of Phases Stability on the Hydrogen Diffusion Coefficient in Ti-6Al-4V

2020 ◽  
Vol 986 ◽  
pp. 33-40
Author(s):  
Mohammed Kasim Mohsun
Keyword(s):  
Heat Treatment ◽  
Diffusion Coefficient ◽  
Titanium Alloys ◽  
Hydrogen Diffusion ◽  
Volume Fraction ◽  
Substantial Effect ◽  
Diffusion Annealing ◽  
Hydrogen Treatment ◽  
Β Phase ◽  
Hydrogen Diffusion Coefficient

For a unique microstructure creation, thermo-hydrogen treatment (THT), using hydrogen as a temporary alloying element within the heat treatment, is applied. This advanced heat treatment requires reliable data about the hydrogen diffusion coefficient (DH) for understanding diffusion kinetics and its effect on the mechanical behavior of the resulted phases. In this research, three different homogeneous microstructures were established for the investigation using different homogenization parameters. After that, the concentration of hydrogen, charged in the half-length of thin titanium rods via electrochemical hydrogenation, is specified. Then, a diffusion annealing heat treatment was carried out at different temperatures, leading to hydrogen diffusion in the hydrogenated specimens. Furthermore, DH was systematically determined using two methods including the explicit finite difference method (EFDM) and Matano technique (MT). For this purpose, Abaqus software was employed for modeling the hydrogen gradient established in the specimens. Additionally, scanning electron microscopy (SEM) was used for the microstructure examination in order to specify the influence of different hydrogen concentrations on the hydrogenated specimens. The experimental outcomes reveal a substantial effect of the β phase stability and grains sizes of the β and α phases on the hydrogen diffusion. Correspondingly, the results confirm that DH was independent of the hydrogen concentration, and obeys an Arrhenius-type temperature dependence. Furthermore, hydrogen diffusion in the α+β titanium alloys Ti-6Al-4V was slower in comparison to the hydrogen diffusion in the metastable β titanium alloys Ti-10V-2Fe-3Al. In conclusion, it was observed that DH is influenced by the previously performed heat treatments that determine the resulted microstructure types, and a slight influence of the volume fraction of the α phase on DH was observed as well.

Chemical partitioning of elements in Ni-base MC-carbide reinforced eutetic superalloys

1983 ◽  
Vol 41 ◽  
pp. 250-251
Author(s):  
E. F. Koch ◽  
E. L. Hall ◽  
S. W. Yang
Keyword(s):  
Alloy Composition ◽  
Volume Fraction ◽  
Lattice Mismatch ◽  
Turbine Blades ◽  
Eutectic Alloys ◽  
Alloy Matrix ◽  
X Ray ◽  
Gas Turbine Blades ◽  
Analytical Electron ◽  
Analytical Electron Microscope

The plane-front solidified eutectic alloys consisting of aligned tantalum monocarbide fibers in a nickel alloy matrix are currently under consideration for future aircraft and gas turbine blades. The MC fibers provide exceptional strength at high temperatures. In these alloys, the Ni matrix is strengthened by the precipitation of the coherent γ' phase (ordered L12 structure, nominally Ni3Al). The mechanical strength of these materials can be sensitively affected by overall alloy composition, and these strength variations can be due to several factors, including changes in solid solution strength of the γ matrix, changes in they γ' size or morphology, changes in the γ-γ' lattice mismatch or interfacial energy, or changes in the MC morphology, volume fraction, thermal stability, and stoichiometry. In order to differentiate between these various mechanisms, it is necessary to determine the partitioning of elemental additions between the γ,γ', and MC phases. This paper describes the results of such a study using energy dispersive X-ray spectroscopy in the analytical electron microscope.

scholarly journals Microstructure and magnetic properties of Nd-Fe-B-(Re, Ti) alloys

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 29-33
Author(s):  
Mariusz Hasiak
Keyword(s):  
Magnetic Properties ◽  
Phase Composition ◽  
Volume Fraction ◽  
Magnetic Characteristics ◽  
Ti Alloys ◽  
Wide Range ◽  
Magnetically Hard ◽  
Ti Addition ◽  
Microstructure And Magnetic Properties

Abstract The microstructure and magnetic properties of nanocomposite hard magnetic Nd-Fe-B-(Re, Ti) materials with different Nd and Fe contents are studied. The role of Re and Ti addition in phase composition and volume fraction of the Nd-Fe-B phase is determined. All samples are annealed at the same temperature of 993 K for 10 min. Mössbauer spectroscopy shows that the addition of 4 at.% of Re to the Nd8Fe78B14 alloy leads to creation of an ineligible amount of the magnetically hard Nd2Fe14B phase. Moreover, the microstructure and magnetic characteristics recorded in a wide range of temperatures for the Nd8Fe79−xB13Mx (x = 4; M = Re or Ti) alloys are also analyzed.

Effect of Coating on the Thermal Conductivities of Diamond/Cu Composites Prepared by Spark Plasma Sintering (SPS)

2014 ◽  
Vol 722 ◽  
pp. 25-29 ◽  
Author(s):  
Q.L. Che ◽  
X.K. Chen ◽  
Y.Q. Ji ◽  
Y.W. Li ◽  
L.X. Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Theoretical Prediction ◽  
Volume Fraction ◽  
Interface Reaction ◽  
Copper Matrix ◽  
Bonding Force ◽  
Ti Alloys ◽  
Plasma Sintering ◽  
Spark Plasma

The carbide forming is proposed to improve interfacial bonding between diamond particles and copper-matrix for diamond/copper composites. The volume fraction of diamond and minor titanium are optimized. The microstructures, thermal properties, interface reaction production and its effect of minor titanium on the properties of the composites are investigated. The results show that the bonding force and thermal conductivity of the diamond/Cu-Ti alloys composites is much weaker and lower than that of the coated-diamond/Cu. the thermal conductivity of coated-60 vol. % diamond/Cu composites is 618 W/m K which is 80 % of the theoretical prediction value. The high thermal conductivity has been achieved by forming the titanium carbide at diamond/copper interface to gain a good interface.

Mechanical Analysis of Low and High Chromium Steels Used in Hot Strip Work Rolls

2018 ◽  
Vol 279 ◽  
pp. 3-9
Author(s):  
Fethi Benkhenafou ◽  
Ines Fernández Pariente ◽  
F.Javier Belzunce ◽  
Abdelkader Ziadi ◽  
Ming Quan Shi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
High Speed ◽  
Volume Fraction ◽  
Research Work ◽  
High Speed Steel ◽  
Nodular Cast Iron ◽  
High Chromium ◽  
Eutectic Carbides ◽  
Hot Strip ◽  
Conventional Heat Treatment

Microstructure, hardness and fracture toughness of low and high chromium high speed steel used in hot strip mills and subjected to conventional heat treatment have been examined. The influence of tempering temperatures on the mechanical properties of these products, determined using tensile and fracture toughness tests, was studied in this research work. The developed microstructures have been characterized by XRD, optical microscopy and SEM examinations. Macrohardness and microhardness of the specimens have been evaluated by Vickers indentation technique. The fracture toughness of these products was investigated using the rupture weight on 3 points bending specimens. The plane strain fracture toughness KIc and the fracture strength were measured for each alloy. The shell is high harness high speed steels, and the core is nodular cast iron. It was found that most fracture occurred in the eutectic carbides formed by the high content alloy element, such as Mo,V,Cr, but that for the alloys with a reduced volume fraction of eutectic carbides, a small amount of crack propagation occurred in the austenitic dendrites.

scholarly journals The Effect of Heat Treatment on the Microstructure and Mechanical Properties of the Novel Low-Cost Ti-3Al-5Mo-4Cr-2Zr-1Fe Alloy

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3798
Author(s):  
Meng Sun ◽  
Dong Li ◽  
Yanhua Guo ◽  
Ying Wang ◽  
Yuecheng Dong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Aging Time ◽  
Volume Fraction ◽  
Low Cost ◽  
Solution Treatment ◽  
Solution Temperature ◽  
The Novel ◽  
Α Phase ◽  
The Cost

In order to reduce the cost of titanium alloys, a novel low-cost Ti-3Al-5Mo-4Cr-2Zr-1Fe (Ti-35421) titanium alloy was developed. The influence of heat treatment on the microstructure characteristics and mechanical properties of the new alloy was investigated. The results showed that the microstructure of Ti-35421 alloy consists of a lamina primary α phase and a β phase after the solution treatment at the α + β region. After aging treatment, the secondary α phase precipitates in the β matrix. The precipitation of the secondary α phase is closely related to heat treatment parameters—the volume fraction and size of the secondary α phase increase when increasing the solution temperature or aging time. At the same solution temperature and aging time, the secondary α phase became coarser, and the fraction decreased with increasing aging temperature. When Ti-35421 alloy was solution-treated at the α + β region for 1 h with aging surpassing 8 h, the tensile strength, yield strength, elongation and reduction of the area were achieved in a range of 1172.7–1459.0 MPa, 1135.1–1355.5 MPa, 5.2–11.8%, and 7.5–32.5%, respectively. The novel low-cost Ti-35421 alloy maintains mechanical properties and reduces the cost of materials compared with Ti-3Al-5Mo-5V-4Cr-2Zr (Ti-B19) alloy.

Growth of AlN by Reactive Gas Injection of Nitrogen in an AlMg Matrix

2014 ◽  
Vol 1036 ◽  
pp. 117-121
Author(s):  
Ildiko Peter ◽  
Raluca Maria Florea ◽  
Oana Bălţătescu ◽  
Ioan Carcea
Keyword(s):  
Quantitative Analysis ◽  
Aluminum Nitride ◽  
Composite Structure ◽  
Volume Fraction ◽  
Primary Objective ◽  
Structure Characterization ◽  
Alloy Matrix ◽  
Typical Structure ◽  
Reactive Gas

The primary objective of the present research was to provide a fundamental understanding of the processing science necessary to fabricate the Aluminum Nitride (AIN) reinforced Aluminum-Magnesium (AIMg) composites via Reactive Gas (N2) Injection in the AIMg alloy melt. Aluminum nitride (AlN) matrix composites were prepared by a novel approach. It was possible to produce a considerable amount of AIN particles in the AI alloy matrix at a reaction temperature as low as 900 °C utilizing the in-situ nitration reaction process developed in the present study. The volume fraction of AIN increases almost linearly with increasing the magnesium (Mg) content in the alloy and the reaction time. The shapes of AIN particles were found to have different forms, whose sizes were in the range from submicron to a few microns. From the present study, it is concluded that the new innovative in-situ nitridation process developed in the present study can be successfully applied for processing of high strength AIMg/AIN composites. For particles and composite structure characterization some methods were used, including: scanning microscopy, quantitative analysis of selected composite regions and XRD analyses. Composite structure and reinforcement distribution was compared with use of quantitative analysis. Morphology and diffraction pattern of aluminum nitride particles was shown. Typical structure of studied composites with microanalysis results was indicated. Aluminum nitride dispersion change was represented.

The effect of solid solution treatment parameters on the microstructure and mechanical properties of A286 superalloy

2021 ◽  
Vol 118 (5) ◽  
pp. 517
Author(s):  
Roya Shahedi ◽  
Shahram Kheirandish ◽  
Faraz Shirazi ◽  
Masumeh Seifollahi
Keyword(s):  
Tensile Strength ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Solution Temperature ◽  
Image Analyzer ◽  
Carbide Phases ◽  
Temperature Ranges ◽  
Electron Microscopes ◽  
The Times ◽  
Scanning Electron Microscopes

In this investigation, the effects of solution parameters on the microstructure and hardness of a Fe-Ni superalloy were studied. Samples were solutionized in temperature ranges of 900 °C to 1060 °C for the times of 0.5 h to 2.5 h, water quenched and aged at 720 °C for 16 h. for more structural examinations, some solutionized samples were aged at 800 °C and 860 °C for 8 h. The microstructure of the alloy was investigated using optical and scanning electron microscopes and the volume fraction of phases was measured by image analyzer software. The hardness of solutionized and aged specimens and tensile strength of aged samples at room temperature were also assessed. The results showed that hardness and ultimate tensile strength decrease with increasing solution temperature. It was found that increase in the solution temperature led to a decrease in volume fraction of η and carbide phases and an increase in the carbide sizes. It was also found that solution annealing time had no significant effect on the properties of the alloy.

Effect of Cooling Rates during a Double Stage Solution Treatment on the Massive Phase Formation in Ti-6Al-4V Alloy

2020 ◽  
Vol 1000 ◽  
pp. 398-403
Author(s):  
Ghozali Suprobo ◽  
Faris Arief Mawardi ◽  
Nokeun Park ◽  
Eung Ryul Baek
Keyword(s):  
Volume Fraction ◽  
Solution Treatment ◽  
Potential Method ◽  
Cooling Rates ◽  
Massive Phase ◽  
Different Temperatures ◽  
Superior Mechanical Properties ◽  
High Fraction ◽  
Transus Temperature ◽  
Specific Temperature

The effect of cooling rates during a double stage solution treatment (DSST) on the volume fraction of the massive phase (αm) in Ti-6Al-4V alloy was successfully confirmed in the present study. The morphology of Ti-6Al-4V alloy depends on the cooling rates during the cooling from the β region. The αm, which has a transformation characteristic between martensite (α′) and α diffusion, is reported to be a potential method for obtaining a fine lamellar α/β by thermal decomposition. The different fraction of αm was found after DSST with the first stage was conducted above the β-transus temperature at 1050 °C, followed by second annealing at different temperatures in the α+β region. It was found that the formation of αm exists in a specific temperature region. A longer period in this region, which was calculated based on different cooling rates during DSST, will increase the fraction of αm in the specimen. All specimens after DSST contain αm with the α width of approximately 1μm and white-dot particles, which is predicted to be V-enriched precipitates. The DSST can be a potential method for producing a high fraction of αm, which can be thermally decomposed into a fine lamellar α/β, introducing a Ti-6Al-4V alloy with superior mechanical properties.

Effect of Solution Treatment Temperature on Microstructure and Mechanical Properties of Al-5.1Zn-2Mg-0.1Ti (wt. %) Produced by Squeeze Casting

2018 ◽  
Vol 939 ◽  
pp. 38-45 ◽  
Author(s):  
Risly Wijanarko ◽  
Irene Angela ◽  
Bondan Tiara Sofyan
Keyword(s):  
Squeeze Casting ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
Ageing Process ◽  
Al Alloy ◽  
Second Phase ◽  
Solution Treatment Temperature ◽  
Phase Volume Fraction ◽  
Ti Addition

Al 7xxx alloy is a heat treatable Al alloy with superior strength. Solution treatment in precipitation hardening sequence of the alloy has an important role to dissolve second phases and bring vacancies out to form precipitates in the ageing process. Another strengthening can be done by Ti addition as grain refiner. As cast alloy by squeeze casting was homogenized at 400 °C for 4 h. Solution treatment was conducted at 220, 420, and 490 °C, followed by rapid quenching. Subsequent ageing was conducted at 130 °C for 48 h. Characterization was performed by optical microscope, SEM-EDS (Scanning Electron Microscopy – Energy Dispersive Spectroscopy), Rockwell hardness testing, XRD (X-Ray Diffraction), and STA (Simultaneous Thermal Analysis). Ti added alloy showed rounder grains, lower hardness, and more reduction in second phase volume fraction along with increasing solution treatment temperature than those in alloys without Ti addition. Otherwise, the alloy final hardness was increasing and higher after the ageing process due to higher second phase dissolution which leads to more precipitates formed.

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