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ID:33660689
大小:1.70 MB
页数:55页
时间:2019-02-28
《含板状wc晶粒硬质合金的制备》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、摘要含板状WC晶粒硬质合金因为同时具备高的硬度和强度而具有广泛的使用价值。本研究分别用w+Co+C和r/(C03W9C4)+Co+C粉末制取含板状WC的WC--Co类硬质合金,系统地研究了球磨工艺、烧,,结工艺、原料粒度、钴含量和碳含量对合金中板状WC的影响以及部分因素对合金力学性能的影响。研究结果表明:延长球磨时间及高球料比都有利于w粉末颗粒细化并扁平,采用高球料比球磨36h后W粉扁平化效果最好,板状的w颗粒原料有利于合金内板状WC晶粒形成;烧结温度为1450"C、保温时间为90min为最佳烧
2、结工艺;与原料粒度为1.0IIm、2.5IIm和14
3、lm的W粉相比,301.tm的W粉最有利于合金内板状WC晶粒的形成,合金的烧结密度、抗弯强度和显微硬度都随着w原料粒度的增大而降低,W粉原料粒度为1.0lIm合金的相对密度最大值为99.692%,抗弯强度最大值为3012MPa,显微硬度最大值1425.1MPa;含板状WC晶的YG20合金与YGl2合金相比,其板状WC晶粒尺寸较小、长厚比较大;在正常的二相区间内,高碳含量有利于合金中板状WC晶的形成;原料粒度相同,使用,7+C州C粉末制得的合金
4、板状WC晶粒粒度要细于直接使用w+C州C制取的合金,,7+Co+C一合金的抗弯强度比w+co+C合金高200多MPa,显微硬度高100MPa。关键词板状WC,硬质合金,力学性能,W+C州℃ABSlRACTCementedcarbidewitllplate-likeshapeWCgrainsc锄becharacterizedbygoodcombinationofhardnessandtoughness.Inthispaper,WC—Cocementedcarbidewhthinplate-like
5、shapeWChasbeenmadebyW+Co+Cand,7(C03W9C4)刊0州℃powders,theeffectofballmillingparameters,sinteringprocess,particlesizeofrawmaterials,cobaltcontentandcarboncontentontheformationofplate·likeshapeWCwasstudied.Theinfluenceofsomefactoronthemechanicalpropertyo
6、ftheplate—enhancedcementedcarbi&wasalsoinvestigated.ResultsshowthatlargerballpercentageandlongermillingtimeGallmaketheparticlesizesmaller,andbecomeplatel·likeshape.Andtheexperimentsindicatedthatundertheconditionoflargerballpercentage,theWparticlecoul
7、dbeflattedeffectively,whichisbenefitofformingplate-likeshapeWCgrains.Thesinteringprocessisoptimizedatabout1450。Cfor90min.ComparetO1.0um、2.5lamand14pm.theWparticlesizeis30/gmwhichfavoredtheformationofplate—likeshapeWCgrains.Thedensity,TRS,microhardnes
8、sofplate—enhancedcementedcarbideisdecreasedwiththeincreaseofWparticlesize.WhenWparticlesizeis1.0Itm,therelativedensity,themaxTRSvalue,themaxmicrohardnessofthealloyare99.692%,3012MPa,and1425.IMParespectively.Theplate—likeshapeWCgrainsizeofYG20issmalle
9、randTTe/aislargerthanthatofYGl2.Inthenormalphaseregion,highercarbonsdowelltotheformationofplate·likeshapeWCgrains.Using玎+co+Cand叭州C,theplate-enhancedcementedcarbidecanbeobtainedrespectivelybythe$anlerawmaterialsparticlesize.Thealloypreparedbyformerme
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