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Interplay between temperature-dependent strengthening mechanisms and mechanical stability in high-performance austenitic stainless steels

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2182-2188页

作者： Mohammad Javad Sohrabi Hamed Mirzadeh Saeed Sadeghpour Milad Zolfipour Aghdam abdol reza geranmayeh reza Mahmudi School of Metallurgy and Materials Engineering College of EngineeringUniversity of Tehran14395-515 TehranIran Centre for Advanced Steels Research Materials and Mechanical EngineeringUniversity of Oulu90014 OuluFinland Department of Mechanical Engineering College of EngineeringUniversity of Tehran14395-515 TehranIran

The effects of deformation temperature on the transformation-induced plasticity(TRIP)-aided 304L,twinning-induced plasti-city(TWIP)-assisted 316L,and highly alloyed stable 904L austenitic stainless steels were compared for the first time to tune the mechan-ical properties,strengthening mechanisms,and strength-ductility *** this purpose,the scanning electron microscopy(SEM),electron backscattered diffraction(EBSD),X-ray diffraction(XRD),tensile testing,work-hardening analysis,and thermodynamics calcu-lations were *** induced plasticity effects led to a high temperature-dependency of work-hardening behavior in the 304L and 316L stainless *** the deformation temperature increased,the metastable 304L stainless steel showed the sequence of TRIP,TWIP,and weakening of the induced plasticity mechanism;while the disappearance of the TWIP effect in the 316L stainless steel was also ***,the solid-solution strengthening in the 904L superaustenitic stainless steel maintained the tensile properties over a wide temper-ature range,surpassing the performance of 304L and 316L stainless *** this regard,the dependency of the total elongation on the de-formation temperature was less pronounced for the 904L alloy due to the absence of additional plasticity *** results re-vealed the importance of solid-solution strengthening and the associated high friction stress for superior mechanical behavior over a wide temperature range.

关键词： austenitic stainless steels mechanical behavior stacking fault energy metastability mechanical twinning

Strength degradation of sandstone and granodiorite under uniaxial cyclic loading

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第1期10卷 117-126页

作者： Rashid geranmayeh Vaneghi Behnam Ferdosi Achola D.Okoth Barnabas Kuek Department of Mining Engineering and Metallurgical Engineering Western Australian School of Mines (WASM) Curtin University

Change in mechanical properties of rocks under static loading has been widely studied and ***, the response of rocks to cyclic loads is still a much-debated topic. Fatigue is the phenomenon when rocks under cyclic loading fail at much lower strength as compared to those subjected to the monotonic loading conditions. A few selected cored granodiorite and sandstone specimens have been subjected to uniaxial cyclic compression tests to obtain the unconfined fatigue strength and life. This study seeks to examine the effects of cyclic loading conditions, loading amplitude and applied stress level on the fatigue life of sandstone, as a soft rock, and granodiorite, as a hard rock, under uniaxial compression test. One aim of this study is to determine which of the loading conditions has a stronger effect on rock fatigue response. The fatigue response of hard rocks and soft rocks is also compared. It is shown that the loading amplitude is the most important factor affecting the cyclic response of the tested rocks. The more the loading amplitude, the shorter the fatigue life, and the greater the strength degradation. The granodiorite specimens showed more strength degradation compared to the sandstone specimens when subjected to cyclic loading. It is shown that failure modes of specimens under cyclic loadings are different from those under static loadings. More local cracks were observed under cyclic loadings especially for granodiorite rock specimens.

关键词： Rock fatigue Cyclic loading Strength degradation Fatigue life

Sources of variability in laboratory rock test results

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第5期13卷 985-1001页

作者： Rashid geranmayeh Vaneghi Seyed Erfan Saberhosseini Arcady VDyskin Klaus Thoeni Mostafa Sharifzadeh Mohammad Sarmadivaleh WA School of Mines:Minerals Energy and Chemical EngineeringCurtin UniversityKalgoorlieWA6430Australia Northern Star Resources KalgoorlieWA6430Australia Science and Research Branch Islamic Azad UniversityTehranIran School of Civil Environmental and Mining EngineeringThe University of Western AustraliaCrawleyWA6009Australia Centre for Geotechnical Science and Engineering The University of NewcastleCallaghanNSW2308Australia WA School of Mines:Minerals Energy and Chemical EngineeringCurtin UniversityKensingtonPerthWA6151Australia

Appropriate rock characterization is beneficial in providing a reliable judgment on rock properties which is crucial for the design process of rock engineering ***,it can be difficult to obtain consistent mechanical parameters due to substantial variations in rock *** this research,uniaxial compression tests on dolerite specimens collected from a gold mine in Western Australia showed substantial scatter in the *** categorization based on the P-wave velocities is as accurate as the thin section analysis,which suggests that they can be used together to gain a more accurate initial understanding of the rock types before any laboratory *** quality of specimen preparation and rockemachine interaction greatly affect the test *** instance,non-parallelness of loading platens can lead to considerable scatter of the testing results,which would be perceived as rock *** is suggested that the current testing standards should be modified towards a better control of the loading machine performance and equipment ***,the possibility of pre-existing microcracks in rock,neither detected by the thin section analysis nor by the ultrasonic measurement,must be examined by computed tomography(CT)scanning as they can affect the test *** study will enhance our knowledge about the sources of variability in laboratory test results of rock which is essential for obtaining reliable data.

关键词： Rock property variation Uniaxial compressive strength(UCS) Specimen preparation End flatness Loading equipment precision Pre-existing microcrack

A modified failure criterion for transversely isotropic rocks

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Geoscience Frontiers 2014年第2期5卷 215-225页

作者： Omid Saeidi Vamegh Rasouli Rashid geranmayeh Vaneghi Raoof Gholami Seyed Rahman Torabi Faculty of Mining Petroleum and Geophysics Shahrood University of Technology Department of Petroleum Engineering Curtin University Rock Mechanics Division Tarbiat Modares University Department of Chemical and Petroleum Engineering Curtin University of Technology

A modified failure criterion is proposed to determine the strength of transversely isotropic rocks. Me-chanical properties of some metamorphic and sedimentary rocks including gneiss, slate, marble, schist, shale, sandstone and limestone, which show transversely isotropic behavior, were taken into consider-ation. Afterward, introduced triaxial rock strength criterion was modified for transversely isotropic rocks. Through modification process an index was obtained that can be considered as a strength reduction parameter due to rock strength anisotropy. Comparison of the parameter with previous anisotropy in-dexes in literature showed reasonable results for the studied rock samples. The modified criterion was compared to modified Hoek-Brown and Ramamurthy criteria for different transversely isotropic rocks. It can be concluded that the modified failure criterion proposed in this study can be used for predicting the strength of transversely isotropic rocks.

关键词： Transversely isotropic rock Strength anisotropy Failure criterion Triaxial test

Photoneutron dose and flux determination of a typical LINAC by MCNP simulation

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Radiation Detection Technology and Methods 2021年第4期5卷 627-632页

作者： Aydin Ghalehasadi Eren Sahiner Saleh Ashrafi Sasan geranmayeh Hadi kasani Niyazi Meriç University of Tabriz TabrizIran Institute of Nuclear Sciences Ankara University06100 Be¸sevlerAnkaraTurkey

Purpose High-energy electron linear accelerators(LINACs)have a wide use in *** photoneutron production in medical linear accelerators,when operating at energies greater than 10 MeV,is an important subject to consider in patient’s treatment *** this work,we simulate a typical LINAC to calculate photoneutron dose and flux in radiotherapy *** The latest version of MCNPX Monte Carlo code along with MCNP visual editor has been used to simulate the LINAC and its *** production has been successfully simulated by selecting appropriate physics card and *** and flux of produced photoneutrons have been calculated by using mesh tally *** Production of photoneutrons in LINAC head and its components have been successfully simulated by using MCNPX *** visual editor has been used to track the *** dose and flux have been calculated using mesh tally function,with good results of statistical *** The photoneutron production has been successfully simulated and *** proposed simulation code is able to calculate photoneutron dose and *** to photoneutron production cross sections,the appropriate parameters have been selected to reduce the run-time of simulation code.

关键词： LINAC Photoneutron Dose Flux MCNPX code