工学部_研究紹介_2020_英語版

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OurresearchgrouphasdevelopedtheCompressionShearingMethodatRoomTemperature(COSME-RT)whereinmetalpowderissimultaneouslyloadedbyashearingforceandacompressivestressinairatroomtemperaturetoformaplate.Usually,heatisnecessaryforpowdermetallurgyformingprocessessuchashotpressing.Incontrast,theCOSME-RTprocessesthepowderatroomtemperature,sograincoarseningdoesnotoccur.Asaresult,theCOSME-RTyieldsgoodmechanicalproperties.Ti-6Al-4Viswidelyusedinbiomechanicalapplications,suchasdentalimplantsandintramedullarynails.However,sincevanadium(V)isdetrimentaltoorganismsandisalsoarareearthelement,V-freebiomaterialsaredesired.COSME-RTcanbeusedtoproducepureTiplatesthatexhibithighstrengthandnanometergrainsizes,makingthismaterialausefulalternativetothecommonbiomaterialTi-6Al-4V.Compression Shearing Method at Room Temperature (COSME-RT): (a)Step 1: metal powder is first placed between a stationary plate and a moving plate in the apparatus. A compressive stress is then applied to the moving plate and maintained during the forming process. (b)Step 2: Finally, a shearing load is added to the moving plate and displaced in the shearing direction.A thin plate is fabricated in this step.Development of Materials Useful in the Fields of Medicine and Welfare The tensile strength of the Ti thin plate formed by the Compression Shearing Method at Room Temperature (COSME-RT) was found to be 3 times larger than that for the rolled Ti.ThegraduatesofNakayamalaboratoryareworkingactivelyinautomotiveindustriesormanufacturesandmetalprocessingfactories.Dr.Eng.AssociateProfessorResearcharea:Plasticworking(powdermetallurgy),Nondestructiveinspection3 timesNoboru NakayamaIn the FutureMechanical Systems EngineeringAfter GraduationWestudydeformationmechanismsofnanometre-scalematerialsbymoleculardynamics(MD)simulations.Itisdifficulttoexploresuchnanometre-scalematerialsexperimentallyduetotheirsize([nm]=10-9[m]).MDisoneofatomicsimulationmethodsandcansimulatethemovementofeachatominamaterial.UsingMD,weperformdeformationsimulationsofvariousmaterialssuchascarbonnanotubesandbulkmetallicglassestorevealthedeformationpropertiesinatomicscales.Inthislaboratory,westudynanometre-scalematerialsusingcomputation-simulations.Carbonnanotubesandbulkmetallicglassesarenewmaterialsdiscoveredrecently.Wehavetounderstandthepropertiesofmaterialsinordertousetheminvariousproducts.Ourstudiesrevealessentialdeformationpropertiesofthesenewmaterials.Basedonourstudies,theymaybeutilizedinvariousfields.Associate Professor2009, Ph. D., Kobe University, Graduate School of Science and Technology. Field of study: Molecular Dynamics simulation, Solid Mechanics.We can discuss deformation mechanisms in nanometre-scale materials by computer experiment. This figure shows torsional or bending deformation analysis of a defective carbon nanotube.Solid Mechanics on Nanometre-scale Materials using Atomic SimulationsComputation-simulations reveal complex changes of atomic structure in materials. This figure shows distributions of atomic strain under the indentation simulation on bulk metallic glasses.Graduatesareworkinginbroadfieldssuchasautoandelectronicsindustries.Inthislaboratory,studentsacquirethecomputation-simulationskillandtheknowledgeinsolidmaterials,whichwillbeveryusefulinyourfuturejobs.MasaomiNishimuraIn the FutureMechanical Systems EngineeringAfter Graduation(a) Depth = 2nm(b) Depth = 4nm(c) Depth = 5nm50nmAtomic strain, γ 0.0 0.510nm14.413.415.4Atomic shear stress [GPa]0-5050Atomic bending stress [GPa]Lattice defect3 times57