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Current progress of research on heat -resistant Mg alloys: A review

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1406-1425页

作者： Hong Yang Wenlong Xie Jiangfeng Song Zhihua Dong Yuyang Gao Bin Jiang Fusheng Pan National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

With the increasing attention received by lightweight metals,numerous essential fields have increased requirements for mag-nesium(Mg)alloys with good room-temperature and high-temperature mechanical properties.However,the high-temperature mechanic-al properties of commonly used commercial Mg alloys,such as AZ91D,deteriorate considerably with increasing temperatures.Over the past several decades,extensive efforts have been devoted to developing heat-resistant Mg alloys.These approaches either inhibit the gen-eration of thermally unstable phases or promote the formation of thermally stable precipitates/phases in matrices through solid solution or precipitation strengthening.In this review,numerous studies are systematically introduced and discussed.Different alloy systems,includ-ing those based on Mg–Al,Mg–Zn,and Mg–rare earth,are carefully classified and compared to reveal their mechanical properties and strengthening mechanisms.The emphasis,limitations,and future prospects of these heat-resistant Mg alloys are also pointed out and dis-cussed to develop heat-resistant Mg alloys and broaden their potential application areas in the future.

关键词： magnesium alloys mechanical properties heat resistance microstructures high temperatures strengthening mechanisms

Morphologic,Radiographic,and Stereomicroscopic Evaluation of Teeth Subjected to high temperatures:An In vitro Forensic Study

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Journal of Forensic Science and Medicine 2023年第3期9卷 228-235页

作者： M.Sai Geethika N.Purnachandra Rao Naik A.Ravi Kiran Y.Samatha B.Naveen Kumar P.Shruthi Sethu Manjusha Saranu K.Pavani Sanjana Marpuri Department of Oral Medicine and Radiology Sibar Institute of Dental SciencesGunturAndhra PradeshIndia

Background:To evaluate morphologic,radiographic,and stereomicroscopic changes of teeth when subjected to specific high temperatures in both direct heat and gradual heat and to compare the changes among two heat groups and also among different types of teeth.Materials and Methods:An in vitro study was conducted on 90 healthy extracted human teeth,in which the teeth were divided into two groups.Group 1(45)was subjected to direct heat and Group 2(45)was subjected to gradual heat.Group 1 and Group 2 were further subdivided into three subgroups(A)anteriors,(B)premolars,and(C)molars each consisting of 15 teeth.Teeth were subjected to temperatures of 200°C,400°C,600°C,800°C,and 1000°C in a muffle electric furnace.The color changes were noted using the Revised Munsell soil color chart and the radiographic and stereomicroscopic changes were evaluated.The results obtained were subjected to statistical analysis.Results:Teeth in direct heat showed more destructive changes at lower temperatures,i.e.,400°C and 600°C when compared to gradual heat where changes are observed at 600°C and 800°C.Among different types of teeth,anteriors and premolars showed more changes when compared to molars.Interpretation and Conclusion:It can be concluded that dental evidence may provide clues to solve the mystery in fire investigations as dental structures are the last to be destroyed under extreme conditions,whether temperature,acid,or putrefaction.

关键词： Color changes in teeth forensic odontology high temperatures incinerated teeth radiographs stereomicroscope

Material Compatibility of Hexamethyldisiloxane as Organic Rankine Cycle Working Fluids at high temperatures

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Journal of Thermal Science 2020年第1期29卷 25-31页

作者： DAI Xiaoye SHI Lin QIAN Weizhong Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Department of Energy and Power Engineering Tsinghua UniversityBeijing 100084China

The organic Rankine cycle(ORC)is a promising technology for industrial waste heat recovery and renewable energy utilization.high temperature ORCs have attracted particular interest because of their high thermal efficiencies and outputs.The material compatibility of working fluid is a significant limitation for the working fluid selection and system design for high temperature ORCs.This work presents a method for studying the material compatibility of ORC working fluids based on the calculated conditions of the ORCs and matching of components,temperatures,and materials.Hexamethyldisiloxane(MM)was chosen as the test fluid.The experimental results show that 304 stainless steel has better compatibility with MM than copper as the material of evaporators.Fluoric rubber is not a suitable sealing material for high temperature ORCs with MM as the working fluids because of the bad compatibility.Mineral oil has better compatibility with MM than polyol ester(POE)lubricant as the lubricant for the fluid pump.

关键词： organic Rankine cycle(ORC) material compatibility high temperatures hexamethyldisiloxane(MM)

FAILURE MODE AND CONSTITUTIVE MODEL OF PLAIN high-STRENGTH high-PERFORMANCE CONCRETE UNDER BIAXIAL COMPRESSION AFTER EXPOSURE TO high temperatures

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Acta Mechanica Solida Sinica 2008年第2期21卷 149-159页

作者： Zhenjun He Yupu Song State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

An orthotropic constitutive relationship with temperature parameters for plain highstrength high-performance concrete （HSHPC） under biaxial compression is developed. It is based on the experiments performed for characterizing the strength and deformation behavior at two strength levels of HSHPC at 7 different stress ratios including a=σs ： σ3=0.00：-1,-0.20：-1,-0.30 ： -1,-0.40：-1,-0.50：-1,-0.75：-1,-1.00：-1, after the exposure to normal and high temperatures of 20, 200, 300, 400, 500 and 600℃, and using a large static-dynamic true triaxial machine. The biaxial tests were performed on 100 mm×100 mm×100 mm cubic specimens, and friction-reducing pads were used consisting of three layers of plastic membrane with glycerine in-between for the compressive loading plane. Based on the experimental results, failure modes of HSHPC specimens were described. The principal static compressive strengths, strains at the peak stress and stress-strain curves were measured; and the influence of the temperature and stress ratios on them was also analyzed. The experimental results showed that the uniaxial compressive strength of plain HSHPC after exposure to high temperatures does not decrease dramatically with the increase of temperature. The ratio of the biaxial to its uniaxial compressive strength depends on the stress ratios and brittleness-stiffness of HSHPC after exposure to different temperature levels. Comparison of the stress-strain results obtained from the theoretical model and the experimental data indicates good agreement.

关键词： high-strength high-performance concrete （HSHPC） high temperatures uniaxial biaxial compressive strength failure criterion stress-strain relationship

A new and reliable model for predicting methane viscosity at high pressures and high temperatures

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Journal of Natural Gas Chemistry 2010年第5期19卷 552-556页

作者： Ehsan Heidaryan Jamshid Moghadasi Amir Salarabadi Faculty of Energy Kermanshah University of Technology Petroleum Engineering Department Petroleum University of TechnologyAhwaz 63431Iran Ilam Gas Treating Company

In recent years, there has been an increase of interest in the flow of gases at relatively high pressures and high temperatures. Hydrodynamic calculation of the energy losses in the flow of gases in conduits, as well as through the porous media constituting natural petroleum reservoirs, requires knowledge of the viscosity of the fluid at the pressure and temperature involved. Although there are numerous publications concerning the viscosity of methane at atmospheric pressure, there appears to be little information available relating to the effect of pressure and temperature upon the viscosity. A survey of the literature reveals that the disagreements between published data on the viscosity of methane are common and that most investigations have been conducted over restricted temperature and pressure ranges. Experimental viscosity data for methane are presented for temperatures from 320 to 400 K and pressures from 3000 to 140000 kPa by using falling body viscometer. A summary is given to evaluate the available data for methane, and a comparison is presented for that data common to the experimental range reported in this paper. A new and reliable correlation for methane gas viscosity is presented. Predicted values are given for temperatures up to 400 K and pressures up to 140000 kPa with Average Absolute Percent Relative Error （EABS） of 0.794.

关键词： methane viscosity falling body viscometer high pressures high temperatures correlation

Bio-Inspired Microwave Modulator for high-Temperature Electromagnetic Protection,Infrared Stealth and Operating Temperature Monitoring

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Nano-Micro Letters 2022年第2期14卷 124-135页

作者： Xuan Yang Yuping Duan Shuqing Li Huifang Pang Lingxi Huang Yuanyuan Fu Tongmin Wang Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116085People’s Republic of China Science and Technology On Power Beam Processes Laboratory AVIC Manufacturing Technology InstituteBeijing 100024People’s Republic of China

high-temperature electromagnetic(EM) protection materials integrated of multiple EM protection mechanisms and functions are regarded as desirable candidates for solving EM interference over a wide temperature range.In this work,a novel microwave modulator is fabricated by introducing carbonyl iron particles(CIP)/resin into channels of carbonized wood(C-wood).Innovatively,the spaced arrangement of two microwave absorbents not only achieves a synergistic enhancement of magnetic and dielectric losses,but also breaks the translational invariance of EM characteristics in the horizontal direction to obtain multiple phase discontinuities in the frequency range of 8.2-18.0 GHz achieving modulation of reflected wave radiation direction.Accordingly,CIP/C-wood microwave modulator demonstrates the maximum effective bandwidth of 5.2 GHz and the maximum EM protection efficiency over 97% with a thickness of only 1.5 mm in the temperature range 298-673 K.Besides,CIP/C-wood microwave modulator shows stable and low thermal conductivities,as well as monotonic electrical conductivity-temperature characteristics,therefore it can also achieve thermal infrared stealth and working temperature monitoring in wide temperature ranges.This work provides an inspiration for the design of high-temperature EM protection materials with multiple EM protection mechanisms and functions.

关键词： Microwave modulator Electromagnetic protection high temperatures Temperature monitoring Carbonized wood

Changes of Mechanical Properties of Lightweight Cement Mortar Mixed with Recycled Expanded Polystyrene and Subjected to high temperatures

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Changes of Mechanical Properties of Lightweight Cement Morta...

Formation of Nanoparticles of Refractory Oxides at high temperatures

2014 International Conference on Green Materials and Environmental Engineering (GMEE2014)

作者： Rocío Sancho ángel Castillo Ma Eugenia Maciá Rosa Corral Polytechnic Superior School CEU San Pablo University Spanish National Research Council–CSIC. Eduardo Torroja Institute of Construction

The main aim of this paper is to evaluate the influence of the recycled expanded polystyrene as lightweight aggregate on the mechanical properties of lightweight cement mortar when subjected to high temperatures. Various tests have been carried out on different mixtures of mortar. The water/cement mix proportion has always been the same and only the nature of the aggregates has changed, with a partial replacement of the conventional aggregate by recycled ground EPS（EPS-G） with values ranging from 10% to 30%, achieving significant results in relation to exposure to high temperatures. In this research, the samples have been subjected to different temperatures of exposure, in order to analyze the influence of the lightweight recycled arid dosage in the mechanical properties of mortars. The results of this study show the ability of mechanical response at high temperatures with light mortars EPS-G. This study shows how this new mix can be used in different building types, optimizing construction materials and reducing mortars density while transforming a residual product into an active product.

关键词： Mortar Lightweight aggregates Mechanical properties high temperatures

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Formation of Nanoparticles of Refractory Oxides at High Temp...

Modelling of temperature and strain rate dependent behaviour of pearlitic steel in block braked railway wheels

第三届国际仪器科学技术学术研讨会

作者： P.Salikhov Physical Technical Institute Mavlyanova 2B 700084 Tashkent Uzbekistan To whom correspondence should be addressed

In measuring thermal radiation properties of cerium dioxide at high temperatures by laser heating technique, three new phenomena related to the interaction of laser radiation with cerium dioxide have

关键词： advanced ceramics cerium oxide cooling high temperatures laser heating nanoparticles thermal radiation properties vapor condensation

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Railway Engineering Science 2021年第4期29卷 362-378页

作者： Ali Esmaeili Johan Ahlstrom Magnus Ekh Dimitrios Nikas Tore Vernersson CHARMEC/Department of Industrial and Materials Science Chalmers University of TechnologyGothenburgSweden Now at Department of Engineering and Physics Karlstad UniversityKarlstadSweden CHARMEC/Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGothenburgSweden

Block braked railway wheels are subjected to thermal and rolling contact loading.The thermal loading results in high temperatures and thermal stresses which cause slow time dependent processes such as creep,relaxation and static recovery of the wheel material.At the same time,the rolling contact loading implies a very fast mechanical load application.This paper is focused on material modeling of pearlitic steel for a wide range of loading rates at elevated temperatures.The starting point is a viscoplasticity model including nonlinear isotropic and kinematic hardening.The Delobelle overstress function is employed to capture strain rate dependent response of the material.The model also includes static recovery of the hardening to capture slower viscous(diffusion dominated)behaviour of the material.Experiments for the pearlitic wheel steel ER7 in terms of cyclic strain-controlled uniaxial tests with hold-time,uniaxial ratchetting tests including rapid cycles and biaxial cyclic tests with tension/compression and torsion are used to calibrate the material model.These experiments were performed under isothermal conditions at different temperatures.In the ratchetting tests,higher loading rates are obtained and these have been used to calibrate the high strain rate response of the viscoplasticity model.The paper is concluded with a numerical example of a block braked wheel where the importance of accounting for the viscoplasticity in modelling is highlighted.

关键词： Block braking high temperatures Pearlitic steel Railway wheels Viscoplasticity