EngRN: Metals & Alloys (Topic)最新文献

{"title":"Development of High-Performance Co-Al-W Alloys by Alloying with Carbon","authors":"H. Kamalia, R. Field, A. Clarke, S. H. Nedjad, M. Kaufman","doi":"10.2139/ssrn.3661924","DOIUrl":"https://doi.org/10.2139/ssrn.3661924","url":null,"abstract":"The microstructures and hardnesses of Co-10Al-9W-1C, Co-7Al-5W-1C and Co-7Al-5W (at %) alloys are reported. Homogenization of the Co-10Al-9W-1C alloy was unsuccessful at 1300 °C and both B2-CoAl and η carbide phases remained in the interdendritic regions. However, the lower-solute Co-7Al-5W-1C and Co-7Al-5W alloys did homogenize at 1300 °C. Upon aging the Co-10Al-9W-1C alloy at 800 °C, the undissolved η carbide transformed into D019-Co3W phase and subsequently into γ'-Co3(Al,W) phase, consistent with the higher stability of the γ' phase in the C-doped alloy. Also, high γ' volume fractions and low γ' coarsening rates were revealed by transmission electron microscopy in the various Co-Al-W-C alloys. These observations are explained by the effect of C on the phase equilibria and γ/γ' interfacial energy in the Co-Al-W system. Finally, the microhardness is increased while the density is decreased by alloying with C, which could result in higher specific strengths in the C-doped alloys.","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123596939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Age-Hardening Response of AlMgZn Alloys with Cu and Ag Additions","authors":"Lukas Stemper, M. Tunes, P. Oberhauser, P. Uggowitzer, S. Pogatscher","doi":"10.2139/ssrn.3559983","DOIUrl":"https://doi.org/10.2139/ssrn.3559983","url":null,"abstract":"Abstract A recurrent challenge with aluminum alloys is their longstanding trade-off between mechanical strength and formability. Recently recyclability has put further pressure on the development of single-alloy concepts for solving this challenge. This study addresses an AlMg-based system featuring additional elements to facilitate age-hardening but retaining a high Mg content for inherent pronounced strain hardening as a potential candidate. Age-hardening was enabled by T-phase based precipitation in the commercial alloy EN AW-5182 via the addition of 3.5 wt.% of Zn. The investigation shows that minor additions of Cu and Ag enhance and accelerate it. The study also compares single-step and double-step artificial aging. Hardness and tensile testing and scanning transmission electron microscopy methods were deployed to characterize the alloys investigated, mechanically and microstructurally. An alloy with added Zn, Cu and Ag showed improved strain hardening and reduced serrated flow in the soft state, while exhibiting an age-hardening response of up to 326 MPa in yield strength leading to an ultimate tensile strength of 550 MPa in peak-aged condition. The study discusses the evolution of the microstructure during artificial aging in the light of Zn, Cu and Ag additions and their effect on the precipitation process.","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122422767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microcrack Initiation Mechanism of a Duplex Stainless Steel Under Very High Cycle Fatigue Loading Condition: The Significance of Load Partitioning and Micro Residual Stresses","authors":"Hongwang Fu, B. Dönges, U. Krupp, U. Pietsch, C. Fritzen, X. Yun, H. Christ","doi":"10.2139/ssrn.3634177","DOIUrl":"https://doi.org/10.2139/ssrn.3634177","url":null,"abstract":"Abstract Investigation on the cyclic response of metallic materials in very high cycle fatigue (VHCF) is a challenging problem, which hinders the development of fatigue theories. To overcome this difficulty, we initially applied several sensible techniques, e.g., High-energy X-ray diffraction (HEXRD), confocal laser scanning microscope (CLSM), nanoindentation and transmission electron microscope (TEM) to investigate the cyclic response of a duplex stainless steel (DSS) in the VHCF regime. In-situ XRD and in-situ digital image correlation (DIC) experiments were subsequently performed at observed changing stages, intending to explore the underlying mechanism of microcrack initiation. The first-hand results obtained revealed that the austenite phase exhibits cyclic softening-hardening-softening behavior during the VHCF process. The in-situ investigations performed at the cyclic softening and hardening stages showed a load partitioning and a load transfer between the two phases, implying the cyclic response can significantly affect the distribution of the applied load. Residual strain obtained by DIC technique after unloading exhibited strong variations at phase boundaries, suggesting micro residual stresses have developed pronouncedly. Based on all the experimental findings, a unified crack initiation mechanism for the investigated DSS during VHCF loading was proposed.","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124499590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elemental Partitioning as a Route to Design Precipitation-Hardened High Entropy Alloys","authors":"F. He, B. Han, Zhongsheng Yang, Da Chen, G. Yeli, Y. Tong, Daixiu Wei, Junjie Li, Zhijun Wang, Jincheng Wang, J. Kai","doi":"10.2139/ssrn.3634180","DOIUrl":"https://doi.org/10.2139/ssrn.3634180","url":null,"abstract":"Abstract Precipitation-hardened high entropy alloys (HEAs) with carefully tuned compositions have shown excellent mechanical properties, demonstrating great potential for engineering applications. However, due to the lack of precise multiple phase diagrams, the composition design of multi-principal-component HEAs still inevitably relies on the extremely time-consuming trial-and-error approach. The present study, on the basis of powerful composition quantification ability of atom probe tomography (APT) technology, proposed a framework to guide the quantitative design of precipitation-hardened HEAs. In this framework, the elemental partitioning was used as a crucial route to avoid the thermodynamic challenge of designing precipitation-hardened HEAs. As a case study, the role of Ti/Al ratio in the design of γ-γ′ HEAs was predicted through the proposed framework and then validated by experimental studies. The framework predicted that when the total content of Ti and Al is fixed, a higher Ti/Al ratio makes γ-γ′ HEA stronger. APT and mechanical results agreed well with these predictions and validated the feasibility of the framework. These findings provided a new route to design the precipitation-hardened alloys and a deeper insight into the design of γ-γ′ HEA.","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122816427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel Approach for the Development of Tailored Heterogenous Structures in Steel","authors":"H. Azizi, Xiang Wang, D. Embury, H. Zurob","doi":"10.2139/ssrn.3610438","DOIUrl":"https://doi.org/10.2139/ssrn.3610438","url":null,"abstract":"Abstract A new strategy is introduced for developing architectured structures in medium carbon steels. The steel is initially decarburized within the austenitic range and quenched to produce a compositionally graded material with 0.4 wt% carbon at the center and 0.1 wt% carbon at the surface. Shear bands developed at the center of the sheet as a result of the cold rolling of the as-quenched microstructure. Subsequent annealing led to the development of nano-scale grains within the shear bands. By controlling the annealing temperature and time, it was possible to produce a wide range of bimodal grain-size distributions. Extended annealing tended to homogenize the material, leading to a fine grained ferrite/cementite microstructure.","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124571065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Situ Micro-Pillar Compression to Examine Radiation-Induced Hardening Mechanisms of FeCrAl Alloys","authors":"Yuchi Cui, E. Aydogan, J. Gigax, S. Maloy, Yongqiang Wang, A. Misra","doi":"10.2139/ssrn.3604622","DOIUrl":"https://doi.org/10.2139/ssrn.3604622","url":null,"abstract":"Abstract The effects of 5 MeV Fe2+ ion irradiation at 300°C on the microstructure evolution and deformation behavior of a FeCrAl C26M alloy are presented. It has been found that dislocation loop density increases an order of magnitude from 1 dpa to 16 dpa irradiations, whereas, the dislocation loop size saturates with increasing damage. Micropillars, 600 nm in diameter and 1.3 µm in height, were fabricated and compressed inside grains with , and crystallographic orientations, respectively. {112} has been identified as the primary slip system in both unirradiated and irradiated alloys. The increase in yield stress after irradiation is observed with measurable variation along and vs. along . By applying the Orowan dispersed barrier model, the increase of yield stress is found mainly due to the slip resistance of radiation generated defect loops. Detailed transmission electron microscopy (TEM) studies were performed to quantify the Burgers vector and the distribution of irradiation induced dislocations at elevated strains. It is revealed that localized shear instability is caused by avalanche slip events of ½ dislocations gliding out of tested pillars. Simultaneously, a large number of sessile/immobile dislocations formed in the vicinity of slip band, leading to the hardening at elevated strains.","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134066019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"X-Ray Photon Correlation Spectroscopy Revealing the Change of Relaxation Dynamics of a Severely Deformed Pd-Based Bulk Metallic Glass","authors":"Hongbo Zhou, S. Hilke, E. Pineda, M. Peterlechner, Y. Chushkin, S. Shanmugam, G. Wilde","doi":"10.2139/ssrn.3582189","DOIUrl":"https://doi.org/10.2139/ssrn.3582189","url":null,"abstract":"Abstract The influence of severe plastic deformation on the relaxation dynamics of a Pd40Ni40P20 (at.%) bulk metallic glass was investigated on the atomic length scale by X-ray photon correlation spectroscopy and fluctuation electron microscopy. At a series of isothermal temperatures adjusted by step heating below the glass transition, the relaxation times were obtained by X-ray photon correlation spectroscopy and the corresponding activation energies were evaluated. It was found that the relaxation dynamics was accelerated by about a half order of magnitude after plastic deformation by high-pressure torsion processing, which indicates that effective rejuvenation has occurred. At relatively low temperatures the relaxation process was stress-dominated and deformation could improve the atomic mobility without changing the energy barrier. At higher temperatures, a second regime of relaxation times occurred. It is concluded that with increasing temperature, a crossover from a stress-dominated to a diffusion-dominated relaxation process occurs. Moreover, the medium range order was measured using variable resolution fluctuation electron microscopy indicating that deformation-induced changes in topology are responsible for the rejuvenation and the accelerated dynamics.","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116426539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of Regularities of the Influence of the Elemental Composition of Niobiumbased Alloys on Their Structure and Properties","authors":"Oleg Sоbоl`, A. Meilekhov, V. Subbotina, O. Rebrova","doi":"10.15587/1729-4061.2020.200264","DOIUrl":"https://doi.org/10.15587/1729-4061.2020.200264","url":null,"abstract":"The method of x-ray diffractometry was used to study the effect of the composition of two, three, four and five elemental niobium-based alloys on their phase-structural state, average crystallite size, and thermal expansion coefficient in the temperature range of +20 °С...–170 °С. As elements of filling, vanadium, tantalum, hafnium, molybdenum, zirconium, tungsten and titanium were used. These elements either in equilibrium – at room temperature (R T =+20 °С), or in high-temperature states have a bcc crystal lattice similar to Nb. It is found that in alloys based on two, three, four and five elements, for the compositions used in the work, the formation of a single-phase state with a bcc crystal lattice of a solid solution occurs. At the structural level, the alloy composition affects the ratio of the intensity of the diffraction peak from different planes. For two diffraction orders from the most closely packed {110} plane in the bcc lattice, a change in the intensity value for the second diffraction order is revealed. The greatest decrease in relative intensity occurs in binary alloys with a large discrepancy in the size of the atomic radii of the components. In multi-element alloys, a smaller drop in intensity is observed. This may be associated with a reduction in the distortion of the crystal lattice due to the ordering of the elements that make up the alloys. At the substructural level, the alloy composition affects the average crystallite size. For binary alloy compositions, the greatest effect is associated with Zr and Hf filling elements having a significantly larger atomic radius. This leads to a decrease in the average crystallite size of the alloy solid solution to the smallest value of 11 nm (NbZr alloy) and the release of the second phase (NbHf alloy). It is found that the coefficient of linear thermal expansion determined by the X-ray diffraction method at 2 temperatures (R T =+20 °С and Т=–170 °С) in multi-element alloys exceeds the values for the starting elements. The largest increase in CTE is observed in alloys containing 17–26 at. % V and W, which have the smallest atomic radius","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131353933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fuel-Cladding Chemical Interaction of a Prototype Annular U-10Zr Fuel with Fe-12Cr Ferritic/Martensitic Cladding","authors":"Xiang Liu, L. Capriotti, Tiankai Yao, J. Harp, M. Benson, Yachun Wang, Lingfeng He","doi":"10.2139/ssrn.3567235","DOIUrl":"https://doi.org/10.2139/ssrn.3567235","url":null,"abstract":"As an alternative fuel form, annular metallic fuel design eliminated the liquid sodium bond between the fuel and the cladding, providing back-end fuel cycle and other benefits. The fuel-cladding chemical interaction (FCCI) of annular fuel also presents new features. Here, state-of-the-art electron microscopy and spectroscopy techniques were used to study the FCCI of a prototype annular U-10wt%Zr (U-10Zr) fuel with ferritic/martensitic HT-9 cladding irradiated to 3.3% fission per initial heavy atom (FIMA). Compared to sodium-bonded solid fuels, negligible amounts of lanthanides were found in the FCCI layer in the investigated helium bonded annular fuel. Instead, most of the lanthanides were retained in the newly formed UZr2 phase at the fuel center region. The interdiffusion of iron and uranium resulted in tetragonal (U,Zr)6Fe phase (space group I4/mcm) and cubic (U,Mo)(Fe,Cr)2 phase (space group Fd3 m). The (U,Mo)(Fe,Cr)2 phase contains a high density of voids and intergranular uranium monocarbides of NaCl-type crystal structure (space group Fm3 m). At the interface of the interdiffusion zone and inner cladding, a porous lamellar structure composed of alternating Cr-rich layers and U-rich layers was observed. Next to the lamellar region, the unexpected phase transformation from body centered cubic (BCC) ferrite (α-Fe) to tetragonal binary Fe-Cr σ phase (space group P42/mnm) occurred and tetragonal Fe-Cr-U-Si phase (space group I4/mmm) was identified. Due to the diffusion of carbon into the interdiffusion zone, carbon depletion inside the HT-9 led to the disappearance of the martensite lath structure, and intergranular U-rich carbides formed as a result of the diffusion of uranium into the cladding. These detailed new findings reveal the unique features of the FCCI behavior of annular U-Zr fuels, which could be a promising alternative fuel form for high burnup fast reactor applications.","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126408747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forming the Structure and the Properties of Electric Arc Coatings Based on High Manganese Steel Alloyed With Titanium and Niobium Carbides","authors":"S. Shihab, P. Prysyazhnyuk, R. Andrusyshyn, L. Lutsak, O. Ivanov, I. Tsap","doi":"10.15587/1729-4061.2020.194164","DOIUrl":"https://doi.org/10.15587/1729-4061.2020.194164","url":null,"abstract":"The formation of the phase composition, structure, and properties of electric-arc coatings by electrode materials based on high-manganese austenite steel, which is strengthened by twinning steel alloyed by titanium and niobium carbides, was studied. Hardfacing alloys were applied using flux-cored arc welding (FCAW ) , which consisted of a shell of low-carbon steel filled with a powder mixture containing ferrosilicon manganese, graphite, rutile, fluorite, carbide of niobium or titanium. The phase composition of the coatings was calculated by the CALPHAD method using the Thermo-Calc and Dictra software to simulate equilibrium and non-equilibrium alloy cooling, respectively. The results of calculations show that the cooling conditions at hardfacing lead to the formation of the structure of metastable manganese austenite and minor (0.2 % by weight) amount of carbide of cementite type M 3 C. This amount of the carbide phase cannot adversely affect the ability of austenite to deformation strengthening. Crystallization of titanium and niobium carbides begins at a high temperature of ~2,400 K and does not affect the phase transformations of austenite into the liquid and solid state. Thus, after cooling, the coating structure mainly consists of two phases, specifically, austenite and niobium or titanium carbide MS in an amount of ~9 vol. %. According to the results from studying the microstructure using scanning electron microscopy and energy-dispersive X-ray spectroscopy of the selected area, the MС carbide phase is released as evenly distributed small particles of the shape that is close to cubic. Carbide particles are mainly located inside austenite grains. Measurement of the hardness of hardfacing coatings shows that at alloying high-manganese austenite steel with niobium and titanium carbides, the hardness significantly increases in hardfacing state from 22 to 35 HRC and after cold plastic deformation from 44 to 52 HRC. The research of wear resistance under conditions of wear by the \"dry sand – rubber roller\" pattern shows that TiC and NbC additives can significantly (by 1.6–1.8 times) improve wear resistance of hardfacing coatings. Due to the ability to deformation strengthening in combination with high abrasion resistance, the obtained materials for hardfacing the systems Fe–Mn–Nb–Si–C and Fe–Mn–Ti–Si–C can be recommended for application to working surfaces of digging machines","PeriodicalId":438337,"journal":{"name":"EngRN: Metals & Alloys (Topic)","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126275080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}