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ID:37232752
大小:3.58 MB
页数:54页
时间:2019-05-20
《粉末冶金铍铝合金相界面微观应力场分析》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、摘要本文通过粉末冶金铍铝合金室温拉伸实验,基于复合材料界面力学理论,建立了以铝为基体,铍颗粒增强的复合材料有限元元胞模型。借助有限元ANSYS软件对该模型进行计算,在单向拉伸和压缩两种情况下,得到了镀颗粒与铝基体界面处的应力值和界面区域的应力场分布。确定了合适的增强体形状。同时,定性的讨论了界面脱粘、裂纹形成与扩展的力学原因。得到如下结论:1.界面处的应力集中状况与增强体颗粒边界的尖锐程度有关。在立方体、椭球形、球形三种颗粒增强模型中,球形颗粒增强体模型界面处的应力值变化较为平缓,在合金的制备过程中,应尽量采用球形颗粒或对颗粒进行钝化处理。2.在拉伸应力作用下,粉
2、末冶金铍铝合金经常于铍铝两相界面处发生脱粘,第一主应力在偏离赤道45度的区域达到最人值,此处是裂纹最容易产生并扩展的区域。在压缩应力场中,屈服应力变化最为明显,在偏离赤道45度的区域达到最大值,屈服在此处最容易发生。3.在拉伸应力场和压缩应力场下,沿界面的裂纹附近各应力场变化也很大。非裂纹尖端应力均平缓下降,而裂纹尖端出现应力集中现象,裂纹在强应力场的作用下极易沿尖端扩展。特别对于压缩应力场,极区附近应力激增,达剑最大值。关键词:铍铝合金,ANSYS,界面,应力场AbstractBasedOiltheroomtensileexperimentsofthepowde
3、rmetallurgyBe-A1alloyandtheinterfacemechanicstheoryofcompositematerials,itestablishesthefiniteelementcellmodelsofcompositematerialsbasedontheilseofAluminumandBerylliumParticlesastheenhancedbodyinthepaper.TheanalyzingmodlesarecalculatedbyANSYSsoftware.Undertensileandcompressivecircumst
4、ancestheinterfacestressvalueandtheinterfaceregionaldistributionofstressisobtained.Itdeterminestheappropriateshapeofenhancedbody.Furtherthequalitativemechanicalreasonsofinterfacedebonding,crackformationandextensionisachieved.Theconclusionsareasfollows:1.,11lefocusofinterfacestressisrel
5、atedtotheboundarysharpoftheenhancedparticles.Inthethreemodelsofcube,ellipsoidandsphericalparticle,theinterfacestressvaluesofsphericalparticlemodelgraduallychange.Inthepreparationofalloy,weshouldusesphericalparticlesortheparticlesofpassivationdisposal.2.Inthecaseoftensilestress,de-bond
6、ingofpowdermetallurgyBe-AIalloyoftenoccurinthetwophasesofBe-AIinterfaces.nefirstprincipalstressisreachedthehighestlevelatthe45degreesofequatorwherethecrackformingandextendingoftenoccourinhere.Inthecaseofcompressstress,theequivalentstresschangesobviously.Andthemaximumyieldstressisalsoa
7、tthe45degreesofequatorwheretheyieldingisthemosteasilyhappeninghere.3.Inthecaseoftensileandcompressstess,thestressdistributionnearcrackalonginterfacechangeobvious,thestressdescendsatthepiontofcrack,andthestressfocusatthepiontofcrackandextendalongthepointofcrack.Especiallyforthecompress
8、stres
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