鎳、鉬、鉻、鎢粉末鋼的組織.pdf

1、南京理工大學(xué)碩士學(xué)位論文鎳、鉬、鉻、鎢粉末鋼的組織姓名：吳曉莉申請學(xué)位級別：碩士專業(yè)：金屬材料及熱處理指導(dǎo)教師：楊德統(tǒng)1999.12.1AbstractlhisanicIchasstudiedtheinfluenceofMo、Ni、Cr、WtothestructureandpropertiesofP／MsteelTheywerepreparedbymixingelementalpowderBym。8115oflnetallographi

2、csection，scarmingelectrionmicroscopy，microprobeanalysisandmicrohardncssmeasurememtetcithasbeenfoundthattheincompletediffusionledtotheinhomogenousmicrostructureinsolidsinteringAt1120。Cwhichisusedformuchofproductionsinteri

3、ng，NidiffusemuchmoreslowlythesinteredmicrostructureisbasicallycomposedofferriteandDcarlite，surroundedbybainintethenmartensitebothhighincarbonandhighinnickel，followedbytheaustenite(originallytheparticlesurfaceandporelocat

4、ions)bothhighinnickelandlowincarbonOfallthecarbideformingmetals，MoisknowntobeoneoftheleastproblenmticmetalswithrespecttothespecificdifficultiespowdermetallurgyInhighMo。AlloyedP／MsteelMopushthepearliticzonestoalongtimeSOt

5、hataustenitetranstbrmtobainitestructuresduringcoolinginthefurnacetoachieve“sinter。hardening”ButitcannotresultinhomogeneousmicrostructuresbysolidstatesinteringMoimprovesthemechanicalpropertiesbothintheassinteredandtheheat

6、treatedstateCrismainmetalofdevelopingwearresistanceandhardness，butcausesproblemsduetoitsoxygenaffinitySinteredinhydrogenabout1％ofCrcanbereduced，SOthatthinoxidationcoverstheCrparticlesandrestrictsthediffusionofCrFromt11cm

7、etallographicsection，theCrparticlesarevisibleSomeagglomerationcanbeformedduringmixingduetothecoalescenceoflineWpowderwhichatleastinpartrenderstheuseofWpowderineflkctix’cWimprovcsthemechanicalpropertiesoftheheattreatedsta