過(guò)剩Si對(duì)6063鋁合金組織與性能的影響

1、過(guò)剩Si 對(duì)6063鋁合金組織與性能的影響張建新1高愛(ài)華2(1.河南理工大學(xué)材料科學(xué)與工程學(xué)院;2.河南理工大學(xué)機(jī)械與動(dòng)力工程學(xué)院摘要研究了過(guò)剩Si 對(duì)6063鋁合金組織性能的影響,并從理論上分析了過(guò)剩Si 的作用機(jī)理。結(jié)果表明,適量過(guò)剩Si 對(duì)合金的鑄態(tài)組織具有細(xì)化效果,并能改善材料的力學(xué)性能;過(guò)剩Si 含量小于0106%時(shí),材料的耐腐蝕性能沒(méi)有明顯變化,過(guò)剩Si 含量超過(guò)0106%時(shí)其耐蝕性能顯著下降;過(guò)剩Si 的增加會(huì)導(dǎo)致材料的導(dǎo)電性能下降,w (Mg /w (Si 小于1173時(shí)其電導(dǎo)率較高。關(guān)鍵詞6063鋁合金;過(guò)剩Si ;組織;性能中圖分類(lèi)號(hào)T G 146.2+1文獻(xiàn)標(biāo)志碼A 文章

2、編號(hào)1001-2249(200802-0148-02收稿日期:2007208206基金項(xiàng)目:河南省教育廳科技攻關(guān)項(xiàng)目(2006430022第一作者簡(jiǎn)介:張建新,男,1972年出生,講師,河南理工大學(xué)材料科學(xué)與工程學(xué)院,河南焦作(454000,電話:0391-*,E -mail :edu001在6063鋁合金中,Mg 、Si 是較為重要的合金元素,由于二者的加入范圍較寬,生產(chǎn)實(shí)際中一般根據(jù)材料的性能要求調(diào)配Mg 、Si 的合理比例,Mg 、Si 的正常質(zhì)量比值為1173,大于或小于1173都會(huì)有過(guò)剩的Mg 或Si 存在1。由于6063鋁合金具有良好的熱塑性、耐蝕性及理想的加工性能,且易氧化著色,

3、被廣泛用于工業(yè)及民用建筑材料、形狀復(fù)雜的導(dǎo)熱導(dǎo)電材料2。為了研究過(guò)剩Si 對(duì)6063鋁合金組織性能的影響,在固定Mg 含量的前提下,利用參數(shù)優(yōu)化法改變Si 的加入量,在試驗(yàn)基礎(chǔ)上詳細(xì)分析了過(guò)剩Si 對(duì)6063鋁合金的鑄態(tài)組織、腐蝕性能及導(dǎo)電性能的影響。1試驗(yàn)方法試驗(yàn)中采用純鋁、純鎂、鋁硅合金配置相應(yīng)6063鋁合金,在功率為7.5kW 的電爐中用石墨坩堝加熱熔煉,溫度達(dá)到760時(shí)加入精煉劑,然后保溫,扒渣后在鐵模中澆注成<85mm 的圓形鑄錠。在560進(jìn)行6h 均勻化處理,用3000kN 油壓機(jī)將圓形鑄錠擠壓成40mm ×10mm 的矩形鋁排,在200進(jìn)行2h 時(shí)效強(qiáng)化。試驗(yàn)材料

4、的鑄態(tài)組織和變形組織分別取樣,用P H IL IPS 2XL30型掃描電鏡觀察其鑄態(tài)組織及斷口形貌,用WEW 21000B 型萬(wàn)能材料試驗(yàn)機(jī)測(cè)定其抗拉強(qiáng)度,用7501渦流導(dǎo)電儀測(cè)量擠壓試樣的導(dǎo)電性能,用物理和化學(xué)方法測(cè)定相應(yīng)的腐蝕性能參數(shù)。2結(jié)果與分析2.1過(guò)剩Si 對(duì)鑄態(tài)組織和力學(xué)性能的影響在6063鋁合金中,Mg 、Si 主要形成強(qiáng)化相Mg 2Si 。為了改善材料的力學(xué)性能,常常人為的調(diào)整二者的比值,當(dāng)w (Mg w (Si <1173時(shí),除形成化合物Mg 2Si 外,還會(huì)有過(guò)剩的Si 存在。研究證明,當(dāng)過(guò)剩Si 含量(質(zhì)量分?jǐn)?shù),下同在0106%以下時(shí),不僅能保持鑄態(tài)組織的細(xì)化效果,

5、而且有助于提高材料的綜合力學(xué)性能(見(jiàn)圖1;當(dāng)過(guò)剩Si 含量超過(guò)0106%時(shí)(以Mg 含量0169%為基準(zhǔn),雖然過(guò)剩Si 不會(huì)降低Mg 2Si 在基體中的溶解度,但它對(duì)鑄態(tài)組織的改善效果開(kāi)始減弱(見(jiàn)圖2,最終導(dǎo)致材料的力學(xué)性能下降 。圖1過(guò)剩Si 含量對(duì)合金力學(xué)性能的影響(a 過(guò)剩Si (b 過(guò)剩Si (c 過(guò)剩Si含量為0含量為0105%含量為0110%圖2過(guò)剩Si 含量對(duì)合金鑄態(tài)組織的影響從圖1、圖2可以看出,適量過(guò)剩Si 對(duì)合金的鑄態(tài)組織影響不大,而過(guò)剩Si 較多時(shí),材料鑄態(tài)組織變得粗大。分析表明:當(dāng)過(guò)剩Si 含量低于0106%時(shí),它對(duì)TiAl 3(雜質(zhì)元素Ti 與基體Al 形成的質(zhì)點(diǎn)的穩(wěn)

6、定性影響很小,這時(shí)Ti 控制下的TiAl 3形核中心占主導(dǎo)位置3;當(dāng)過(guò)剩Si 含量超過(guò)0106%時(shí),過(guò)剩Si 對(duì)TiAl 3的穩(wěn)定性有一定影響,這時(shí)Si 控制下的TiAl 3結(jié)晶核心占主導(dǎo)地位,部分過(guò)剩Si 與Ti 、Al 一起形成AlSi Ti 三元化合物4,減少了TiAl 3質(zhì)點(diǎn)的數(shù)量,故降低了形841輕有色合金特種鑄造及有色合金2008年第28卷第2期核率。2.2過(guò)剩Si 對(duì)腐蝕性能的影響Si 在Al 中的溶解度很小,共晶溫度下為1165%,室溫時(shí)僅為0105%。為了研究6063鋁合金中溶解少量過(guò)剩Si 對(duì)材料的腐蝕性能的影響,在室溫條件下,將一定質(zhì)量試樣浸入315%的NaCl +1%的

7、H 2O 2的腐蝕介質(zhì)中72h 后,取出晾干,再次用物理天平稱(chēng)取質(zhì)量結(jié)果見(jiàn)表1。結(jié)果表明,當(dāng)過(guò)剩Si 含量不高于0106%時(shí),過(guò)剩Si 不僅有助于提高合金的力學(xué)性能,而且對(duì)合金的抗腐蝕性能也無(wú)明顯影響;當(dāng)過(guò)剩Si 含量超過(guò)0106%時(shí),會(huì)降低材料的抗腐蝕性能,并且易在晶界處偏聚。表1過(guò)剩Si 含量對(duì)合金腐蝕性能的影響序號(hào)過(guò)剩Si 含量/%腐蝕前質(zhì)量/g腐蝕后質(zhì)量/g質(zhì)量相對(duì)損失率/%10 5.31793 5.293420.460920.03 5.26578 5.241450.462130.06 5.12597 5.101200.483340.095.093265.059920.6545分析表明

8、,鋁鎂硅系合金產(chǎn)生腐蝕的典型現(xiàn)象是局部點(diǎn)腐蝕。從電化學(xué)腐蝕的機(jī)理看,引起局部點(diǎn)蝕的重要原因是微電池的形成。一般說(shuō)來(lái),成分及組織的均勻性提高,可降低各部位的電勢(shì)差,因而可抑制微電池的形成,也就是說(shuō)組織的晶粒越細(xì)小、越均勻,腐蝕中形成微電池的概率越小。因此,當(dāng)過(guò)剩Si 含量適中時(shí),材料的鑄態(tài)組織較為細(xì)小均勻,所以它的抗腐蝕性能降低很小;當(dāng)過(guò)剩Si 含量達(dá)到0106%以上時(shí),過(guò)剩Si 容易在晶界處發(fā)生偏聚,導(dǎo)致材料的均勻性下降(見(jiàn)圖3。除此之外,過(guò)剩Si 還可與 Fe 、Al 一起形成Al FeSi 相,該相對(duì)于鋁基體是陰極相,它們二者恰好構(gòu)成一對(duì)電極電偶,這種條件下材料的抗腐蝕性能會(huì)大大下降。所以

9、,在實(shí)際生產(chǎn)中,為了改善材料的力學(xué)性能,常常使過(guò)剩Si 含量不超過(guò)0106%,以免給合金材料的抗腐蝕性能帶來(lái)負(fù)面影響4,5。圖3晶界處析出的過(guò)剩Si2.3過(guò)剩Si 對(duì)導(dǎo)電性能的影響鋁合金中的合金元素是影響其導(dǎo)電性能的主要因素之一,這主要取決于其他元素的加入量和存在形式6。試驗(yàn)中固定Mg 的加入量,適當(dāng)改變Si 的含量熔煉相應(yīng)試樣,測(cè)得的試驗(yàn)數(shù)據(jù)見(jiàn)表2,可以看出,隨著過(guò)剩Si 含量的降低,合金的導(dǎo)電能力是增加的,增加過(guò)程在略小于1173時(shí)終止,然后隨著過(guò)剩Mg 含量的增加,合金的導(dǎo)電能力急劇下降。表2過(guò)剩Si 對(duì)電導(dǎo)率的影響序號(hào)w (Mg /w (Si 過(guò)剩硅含量/%過(guò)剩鎂含量/%電導(dǎo)率/(MS

10、 m -11 1.540.05-28.22 1.650.02-29.63 1.730.000.0029.34 1.78-0.0227.951.85-0.0526.2一般來(lái)說(shuō),合金元素影響基體組織的均勻性和純凈度,均不利于導(dǎo)電,并且固溶態(tài)元素對(duì)合金電導(dǎo)率的影響遠(yuǎn)大于析出態(tài)元素7的影響。因此,除了由于合金元素的加入產(chǎn)生第二相作用外,幾乎所有的合金元素都降低合金的電導(dǎo)率。當(dāng)過(guò)剩Si 含量較少時(shí),組織中微量的Si 剛好與雜質(zhì)元素Fe 彌散分布于鋁基體中,二者形成粗大(Al 9Fe 2Si 2相的幾率很小,所以合金的導(dǎo)電能力良好;當(dāng)過(guò)剩Si 含量較多時(shí),過(guò)剩Si 不僅固溶于鋁基體中,并且w (Si /w

11、 (Fe 適當(dāng)時(shí),極易向粗大相轉(zhuǎn)化,因此導(dǎo)電能力有所下降。當(dāng)w (Mg /w (Si 大于1173時(shí),過(guò)剩Mg 元素不僅削弱Mg 2Si 的強(qiáng)化機(jī)制,還增加了自身在基體中的固溶度8,所以合金的導(dǎo)電性能急劇下降。3結(jié)論(1適量過(guò)剩Si 含量能改善6063鋁合金的鑄態(tài)組織及綜合力學(xué)性能,當(dāng)過(guò)剩Si 含量超過(guò)0106%時(shí),材料的組織和力學(xué)性能有所下降。(2組織中的過(guò)剩Si 含量小于0106%時(shí),它對(duì)6063鋁合金的抗腐蝕性能影響不大,過(guò)剩Si 含量較多時(shí)材料的抗腐蝕性能顯著下降。(3隨著組織中過(guò)剩Si 含量的增加,6063鋁合金的導(dǎo)電性能是下降的,一般在w (Mg /w (Si 略小于1173時(shí)合金

12、具有較高的導(dǎo)電性能。參考文獻(xiàn)1武恭,姚良均,李震夏,等.鋁及鋁合金材料手冊(cè)M .北京:科學(xué)出版社,1994.2張萬(wàn)金,李霞,王貴福,等.Al 2Si 系變形鋁合金初晶硅尺寸的控制J .輕合金加工技術(shù),2006,34(4:729.3陰瑜娟,趙玉厚,夏永喜.原位生成Al 3Ti 和TiB 2增強(qiáng)鋁基復(fù)合材料的研究J .鑄造技術(shù),2007,28(3:3442346.4張建新,高愛(ài)華,曹新鑫.提高Al 2Mg 2Si 系合金強(qiáng)度的途徑分析J .鑄造技術(shù),2006,27(4:3672369.5張建新,高愛(ài)華,陳昊.合金元素對(duì)Al 2Mg 2Si 系鋁合金組織及性能的影響J .鑄造技術(shù),2007,28(3

13、:3732375.6楊伏良,甘衛(wèi)平,陳招科.硅含量對(duì)高硅鋁合金材料組織及性能的影響J .材料導(dǎo)報(bào),2005,19(2:982100.7趙乃勤,姚家鑫,楊賢金.稀土對(duì)6063鋁合金組織性能的影響J .天津大學(xué)學(xué)報(bào),1995(3:3762378.8顏建輝,陳輝煌.熱處理工藝對(duì)6063鋁合金強(qiáng)度和電導(dǎo)率的影響J .熱加工工藝,2004(2:49250.(編輯:栗萬(wàn)仲941過(guò)剩Si 對(duì)6063鋁合金組織與性能的影響張建新等tensile test.SEM o bservation reveals t hat in2sit u syn2 t hesized fine Al3Zr and Al2O3par

14、ticles wit h23m in size can be observed,which is uniformly distributed into t he matrix due to not be rejected by solid/liquid interface but be engulfed in t he solid p hase,and t he Si p hase in t he A356alloy can be converted f rom coarse acicular into fine particle wit h trace Sr modification. Th

15、e tensile strengt h of t he Sr modified composites is increased by1318%compared wit h t hat of t he com2 posites wit ho ut Sr modification.K ey Words:Aluminum Matrix Composites,Microstruc2 ture,Mechanical Properties,Sr Modif ication Preparation of Ni2CeO2N ano2composites by Electro2 forming in an U

16、ltrasonic Field Xue Y ujun1,Li J i shun1,2,Li Ha ng1,Ma Wei1,Sun Y o ng1(1.School of Elect romechanical Engineering,Henan University of Science and Technology,L uoyang,China; 2. Henan Laboratory of Modern Mechanical Design and Transmission System,L uoyang,China2008,28(2 142144Abstract Ni2CeO2nano2co

17、mpo sites were prepared by e2 lect roforming in an ult rasonic field.The effect s of ul2 t rasonic power,CeO2nano2particle addition and cat h2 ode current density on t he content of CeO2in t he nano2 composites have been investigated,and t he elect rofor2 ming velocity and current efficiency wit h t

18、 he ult rasonic effect have been analyzed.The surface morp hology and micro2hardness of t he nano2compo sites have been examined.The result s indicate t hat t he desirable Ni2 CeO2nano2compo sites containing310%CeO2can be p repared wit h t he CeO2particles addition of40g/L and ult rasonic power of30

19、0W at frequency of28k Hz and cat hode current density of6A/dm2,exihiting more smoot h morp hology wit h more compact struct ure and finer grain size,compared wit h t hat of Ni2CeO2 nano2compo sites p repared in t he absence of ult rasonic field.The ult rasonic field can promote t he co2deposi2 tion

20、of nano2particle wit h t he matrix to f urt her refine t he grain size as a result of rest raining t he agglomera2 tion of t he nano2particle,and it can obviously increase t he micro2hardness of t he composites as well as raising t he elect ro2forming speed and electric current efficien2 cy.K ey Wor

21、ds:U ltrasonic Field,Electro2forming, CeO2P article,N ano2compositesMicrostructure and Properties of In2situ Synthesized Ti2AlC/TiAl Composites Li Y unming,Wa ng Fen,Liu Ningya n,Zhu J i a nfeng(School of Materials Science and Engineering,Shaanxi U niversity of Science and Technology,Xian,China2008,

22、28(2145147 Abstract The micro st ruct ure and properties of in2sit u Ti2AlC/TiAl co mpo sites synt hesized by vacuum p res2 sure sintering in Al2Ti2C system were investigated by XRD(X2ray diff ractometer,SEM(scanning elect ron microscope,OM(optical microscopeand tensile test,and t he reinforced mech

23、anism of Ti2AlC in TiAl alloy was app roached.The result s indicate t hat t he composites are composed of Ti2AlC reinforcement,a few amount s of Ti3AlC p hase and TiAl mat rix.The creation of lamellar Ti2AlC reinforcement can refine t he matrix grain size and rest rain t he p ropagation of crack,gre

24、atly imp roving t he mechanical p roperties of t he composites.The bending st rengt h and f ract ure toughness of t he composites reach743184M Pa and 9117M Pam1/2,respectively.K ey Words:Ti2AlC/TiAl Composites,In2situ Synthe2 sization,Mechanical Properties,R einforced Mechanism Influence of Surplus

25、Si on Microstructure and Properties of6063Aluminum Alloy Zha ng J i a nxin1,Gao Aihua2 (1.Instit ute of Materials Science and Engineering, Henan Polytechnic U niversity,Jiaozuo,China;2.In2 stit ute of Mechanical and Dynamic Engineering, Henan Polytechnic U niversity,Jiaozuo,China2008, 28(2148149Abst

26、ract The effect s of surplus Si on microst ruct ure and properties of6063aluminum alloy were ap2 p roached,and t he mechanism of t he surplus Si was analyzed t heoretically.It was found t hat t he proper surplus2Si can refine as2cast microst ruct ure and im2 p rove t he mechanical p roperties of t h

27、e6063aluminum alloy.The effect s of surplus Si content wit h less t han 0.06%on t he corrosion resistance of t he alloy can be neglected,however,excessive surplus Si content can significantly deteriorate t he corrosion resistance.The elect ric conductivity of t he alloy can be declined wit h t he in

28、crease of surplus Si content,and t he higher elec2 t ric conductivity can be observed wit h t he mass ratio of Mg via Si somewhat less t han1.73.K ey Words:6063Aluminum Alloy,Surplus Si,Micro2 structure,PropertiesAs2cast Microstructure of Mg25Sn2x G d Alloys Niu Gao, Chen Y ungui,Ta ng Y o ngbai,X i

29、 ao Sufen,Zha ng X i2 aoping,Wei Sha nghai,Zhao Y ua nhua(School of Materials Science and Engineering,Sichuan Universi2 ty,Chengdu,China2008,28(2150152Abstract The as2cast microst ruct ures of Mg25Sn2x Gd (x=0,0.5,1.0,4.0,6.0alloys have been ob2 served.The experimental result s indicate t hat wit h in