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1.
1 INTRODUCTIONTitaniumaluminidesareattractivecandidatema terialsforaerospacestructuralandengineapplica tions ,owingtotheirlowdensi  相似文献   

2.
1 INTRODUCTIONBioleachingprocesseshavebeenusedextensivelytorecoverbasemetals (mainlycopper)anduraniumfromlow gradeoresandmorerecen  相似文献   

3.
1 INTRODUCTIONMechanicalactivationiswidelyappliedinen hancingmetallurgicalprocess[1~ 3] andchemicalsyn thesis[4 ,5] .Sofaritisdifficultt  相似文献   

4.
1 INTRODUCTIONMagnesiumalloyshavemanyadvantagessuchaslowdensity ,highspecificstrength ,goodelectromag neticshieldingcharacteristics ,excellentcastabilityandmachinabilityetc .Magnesiumisanabundantele mentsinceabout 1.93% (massfraction)ofearthcrustconsistofmagne…  相似文献   

5.
1 INTRODUCTIONNi3AlbasedalloyIC6,whichisadirectionallysolidifiedhightemperaturestructuralmaterial,hasbeenrecentlydevelopedbyBeijin  相似文献   

6.
Role of Al2O3 fiber in eutectic Al-Si alloy composites   总被引:1,自引:0,他引:1  
1 INTRODUCTIONMetalmatrixcomposites (MMCs)havemanyimportantapplicationsinaircraftandautomobilein dustry ,fortheyhavemanyadvantagess  相似文献   

7.
1 INTRODUCTIONTheinterestindevelopinghighstrengthwithhighconductivitycopper basedalloyshasledtoacon stanteffortonmodifyingtheallo  相似文献   

8.
1 INTRODUCTIONThedirectionallysolidifiedNi3AlbasealloyIC6AwiththechemicalcompositionofNi (7.5~8.5 )Al (13.0~ 15 .0 )Mo (0 .0 2~ 0 .1)B (0 .0 0 5~0 .0 5 )Y (massfraction ,% )hasbeenrecentlydevel opedbasedonalloyIC6asahigh temperaturestruc turalmaterialusedforadvancedjet enginevanesop er…  相似文献   

9.
1 INTRODUCTIONThecorrosionofachromatezincattheinitialstageisthedecreasing processofsurfacelightness ,andisusuallycalledmelanization (black patina)ofzincplateofwhichtheproductisZn1 δOwiththepropertyofann typesemi conductor ,andtheillumi nationsuppressestheme…  相似文献   

10.
1 INTRODUCTIONThestudyofmoltenstructureofCaO SiO2 ,whichactasthebasicfactorinfluencingthephysicalandchemicalpropertiesofthesilicat  相似文献   

11.
1 INTRODUCTIONTheimportantbacteriainbiohydrometallurgyaremainlyaerobicchemolithotrophicspecies ,ofwhichthemoreimportantareThiobacillusferrooxi dansandThiobacillusthiooxidans .ThepropertiesofthetwospeciesareshowninTable 1.Theycatalyzetheoxidationofsomeora…  相似文献   

12.
Behavior of Fe and S in bioleaching of pentlandite   总被引:4,自引:1,他引:4  
1 INTRODUCTIONOxidizingprocessbyautotrophicbacteria ,suchasThiobacillusferrooxidans (Hereinbelowbeabbre viatedtoT .f .) ,hasbeenwidely  相似文献   

13.
1 INTRODUCTIONHydrogenreductionoftungstenoxides,subsequentmixingwithcarbonblackandcarburatingisthemostcommonwaytoproducetungstencarbidepowdersforthehardmetalindustry.Thistechniquehasbeenpracticedfordecadesandcalled“conventionalhydrogenreductionprocess…  相似文献   

14.
1 INTRODUCTIONTheevolutionoftextureinaluminumanditsal loysduringdeformationandannealinghasbeeninves tigatedusingtheelectronbackscatteringpattern (EB SP)techniqueinascanningelectronmicroscope(SEM )andtheorientationdistributionfunctions(ODFs)usedforanumberof…  相似文献   

15.
1 INTRODUCTIONOwingtotherequirementsofrepeatedserviceandlongworkingtimeofhightemperatureburners ,suchasspacecraftengine ,thematerialoftheburnersshouldhavegoodstructureprocessability ,aswellashightemperatureresistance ,thermalshockresistanceandthermalfati…  相似文献   

16.
1 INTRODUCTIONRelativelylargeundercoolingisgainedinbulkal loymeltwithmoderatecoolingratebyeliminatingthesolidinclusionsinthemeltandbyeliminatingtheef fectofcontainerwallonthetriggeringofnucleation .Theaccumulateddrivingforceforcrystallizationcaus esrapi…  相似文献   

17.
1 INTRODUCTIONThereliabilitydesignoptimizationofmachinecomponentisbasedonthefoundationofneotericmathematicalprobability ,mathematicalstatisticsandoptimization .Itusuallydealswithhighdimensional,nonconvexandnonlinearobjectfunctionssubjecttovariousstochas…  相似文献   

18.
Control of deflection deformation of plate-shape castings in solidification   总被引:1,自引:0,他引:1  
1 INTRODUCTIONAnorderoflargeplatecastingsusuallybafflesthemanufactures,asthedeflectiondeformationisliabletooccurduringsolidificationofthecastings .Thecommonwaytosolvethisproblemistopursueanoptimumcastingprocessroutebytrialanderrormethod ,ortokeeplargerm…  相似文献   

19.
1 INTRODUCTIONTheobligatechemoautotrophicbacteriawhichisnamedThiobacillusferrooxidans,istheprimaryor ganismimplicatedinthebioleachingofseveralsul fides .Itscommercialpotentialintherecoveryofmet alfromlow gradeandrefractoryores ,desulfurizationofcoals ,andi…  相似文献   

20.
1 INTRODUCTIONNewmaterials ,suchasdispersionstrengthenedalloy ,amorphousandintermetallics ,canbeobtainedbymechanicalalloyingwhichsh  相似文献   

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