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1、碗}論文超纓配錒的電鑄T藝優(yōu)化研究摘要本文進行了雙向脈沖電鑄超細(xì)晶銅實驗,通過改變脈沖參數(shù),分別使用掃描電子顯微鏡和透射電子顯微鏡觀察電鑄層的形貌和晶粒尺寸大小的變化規(guī)律,并探討了金屬電解沉積和結(jié)晶過程的機理。試驗表明雙向脈沖電鑄能得到結(jié)構(gòu)細(xì)致的超細(xì)晶銅。隨著正向平均電流密度的增加,晶粒尺寸逐漸減小,結(jié)晶細(xì)致,但電流密度過大時,晶粒尺寸幣新變大,鑄層會被燒焦:隨著正向占宅比,,4-的增加,晶粒尺寸逐漸增大;隨著正向頻率f+的增加,晶粒尺寸逐漸減小。此外,反向的脈沖參數(shù)也可改變鑄層形貌和晶粒尺寸的大小,但其作用效果不如正向脈沖參數(shù)明顯。超細(xì)晶錒的平均晶粒尺寸為450n
2、to左右,其中強度得到顯著提高,為普通粗鈳的2倍左右,最高的屈服強度達(dá)到546.8MPa,抗拉強度達(dá)到682.1肝a,但延伸率較低,一般在10%以F。其中晶粒細(xì)化和啞晶中存在大最的位鍺疇肇為強度提高的E要原因。存在大最攣晶的電鑄層強度有所下降,延伸率增加。主要是位錯在大攣晶中易于移動,從而造成強度下降,顰性提高。對超細(xì)晶銅進行熱處理,觀察到晶拉長大、孿晶減少的過程,造成強度下降,延伸率上升至20%左右。關(guān)鍵詞:脈沖電鑄,脈沖參數(shù),孿晶,高強度矽士論文超細(xì)晶鍘的電鑄r藝優(yōu)化研究abstractBidirectionalimpulseelectroformingsupe
3、r—finegraincopperexperimentwasconductedinthispaper.theappearancesandcrystaldimensionofelectronicdepositionlayerformedunderdifferentparametersofelectronicimpulsewasobservedbyTEMandSEM,andmechanismofthemetalelectroanalysissedimentprocessandcrystallizationwasdiscussed.Theresultsshowsthats
4、uper—finegraincoopercanbeobtainedbyBidirectionalimpulseelectroforming.Withtheincreaseofpositivecurrentdensity,grainsizedecreased,andthecrystalwasfined;butifthei+isexcessivethanacertainvalue,thegrainsizewillgetenlargedoveragain,andthedepositionlayerwiIIbebadlyburned:andtheincreaseofanod
5、e,,+willmakethegrainsizegrowgradually;andiftheanodefrequencyfincreased.thegrainsizewillbesmaller.Furthermore,cathodeelectronicimpulseparametersalsocanaffectappearancesofthedepositionlayerandthegrainsize,althoughtheimpactisnotasdistinctasthepositiveone.Theaveragegrainsizeofsuperfinecopp
6、erisabout450am,andthestrengthisgreatlyimproved,whichisabouttwotimesasstrongasthecommoncoarsecopper.Theyieldstrengthisashighas546.8MPa,,whilethetensilestrengthreaches682.IMP&Itisthatfinedgrainsizeandalargenumberofdislocationdomainwallsexistinginsub—grainthemaincauseofstrengthincrease.Th
7、eintensityofelectronicdepositionlayerwithmanytwinsfalIs,whiletheelongationincreases.Itismainlybecausethatdislocationslideseasilywithinlargetwincrystal,whichleadstothedecreaseofstrengthandtheincreaseinplasticity.Afterthesuperfinecopperwasheattreated,grainsizegrowingandquantityoftwinsd