简介:采用Gleeble-1500热模拟机高温压缩试验,研究5A01铝合金在应变速率为0.01~1s^-1、变形温度为350~450℃条件下的流变行为,并利用光学显微镜分析合金在不同压缩条件下的组织形貌特征。结果表明:应变速率和变形温度的变化强烈影响合金流变应力的大小,流变应力随变形温度升高而降低,随应变速率提高而增大。采用双曲正弦形式ARRHENIUS的关系来描述5A01铝合金高温压缩变形时的流变应力行为,获得的材料常数A、a、11和Q分别为0.06831s^-1、0.0094MPa、2.7089和161.14kJ/mol;在应变速率为0.01s^-1叫及变形温度低于400℃条件下变形时,5A01铝合金组织为纤维组织,而当变形温度升高到450℃时,再结晶程度很高,出现大量等轴晶。
简介:Heterogeneousprecipitationmethodwasusedtopreparedsurfacecoatingonself-madeBaMgAl10O17:Euphosphor.Resultsillustratethatthecoatingfilmcanbesilicondioxideinamorphousstatewith50nminthickness.Photoluminescenceresultsindicatethatthecoatinglayerpresentsanobservableimprovedeffectontheenhancementofthermalstability.Whenbakedat600℃for1h,theluminanceofcoatedBAMkeepsat92%higherthanthatofuncoatedBAMby23%.ThisprotectiveeffectcanbeattributedtothehighcompactdegreeanduniformityofthisamorphousSiO2coatingfilmwhichisservedasadiffusionblocklayertoinbreakoxygenatom,thusreleasestheoxidationextentofEu2+effectively.
简介:Inordertoutilizetheadvantageofoxidesinstainlesssteel,theformationoftitaniumnitride(TiN)andoxide(TixOy)inthe17CrsteelwasinvestigatedbythecalculationofthefreeenergyofreactionandthermodynamiccalculationwithThermo-calcsoftware.Theresultindicatesthatthecompetitivereactionbetweenthedissolved[O]andthedissolved[N]withthedissolved[Ti]inmoltensteelresultsindifferentprecipitationsequencesofTiNandTixOy.TheprimaryprecipitationofTiNrequiresalow[O]andtheprimaryprecipitationofTixOyrequiresalow[N].Theincreaseof[Ti]causesahigherprecipitationtemperatureofTiNandTixOyinbothTi-NandTi-Oalloysystems.Equilibriumrelationsof[Ti]vs[N]and[Ti]vs[O]showthatthesolubilityproductsfallwiththedecreaseofthetemperature,andthentheprecipitationoftheinclusionsbecomeseasier.IntheTi-Oalloysystem,ahigh[O]andalow[Ti]arefavorabletotheprecipitationofTi3O5,andahigh[Ti]contentandalow[O]favorabletotheTi2O3precipitation.
简介:利用粉末冶金方法研制了Sm(CobalFe0.24Cu0.08Zr0.027)7.0,Sm(CpbalFe0.27Cu0.05Zr0.027)7.0,Sm(CobalFe0.26Cu0.05Zr0.026)7.03种高温永磁,并对其磁性能、温度稳定性和显微结构进行了分析.结果表明:样品Sm(CobalFe0.27Cu0.05Zr0.027)7.0具有最高的内禀矫顽力(2165.6kA·m-1)和最大磁能积(212.0kA·m-3);3种磁体的温度系数都较低,最高使用温度均在400℃以上,大大高于一般商用磁体;增加Sm,Co,Cu的含量和减少Fe的含量可以提高材料的温度稳定性.X射线分析表明,合金中含有Sm2(Co,Fe)17主相,Sm(Co,Cu)5相,含Zr化合物等.Sm(Co,Cu)5相、单质Zr、晶粒边界等钉扎畴壁,使合金具有较高的矫顽力.
简介:La1.5Mg17Ni0.5hydrogenstoragematerialswerepreparedbyhydridingcombustionsynthesis(HCS)andmechanicalalloying(MA)methodrespectively.TheexperimentalresultsshowthatthehydrogenabsorptionpropertiesofLa1.5Mg17Nio.5preparedbyMAarebetterthanthatbyHCS.La1.5Mg17Nio.5preparedbyMAcanabsorb6.73mass%hydrogenat523Kwithin1min,and4.92mass%hydrogenat423K.TheimprovementofhydridingpropertiesofLa1.5Mg17Ni0.5alloypreparedbyMAcanbeascribedtotheformationofnano-crystallineanddefectsduringthemechanicalalloying.
简介:分析了影响45Mn17Al3钢磁导率性能的主要因素。通过工业试验确定了合理的化学成分、热处理工艺制度及试样表面加工要求等。试验结果表明,45Mn17Al3钢在800、4000及8000A/m三个磁场强度下,相对磁导率μr≤1.005,满足了某些特殊工程对磁性能的较高要求。