顆粒尺寸對(duì)鎢銅合金組織性能及電弧燒蝕特性的影響
發(fā)布時(shí)間：2019-05-16 16:26
【摘要】：鎢銅合金因其良好的導(dǎo)電、導(dǎo)熱、耐電弧侵蝕性及抗熔焊性被廣泛應(yīng)用于觸頭材料、電極材料、航空航天用耐燒蝕材料。眾所周知,粗晶材料有較好的高溫性能,但細(xì)晶的鎢銅合金具有分散電弧、耐電弧燒蝕性。針對(duì)不同應(yīng)用場(chǎng)合的鎢銅合金,本文采用不同粒度的鎢粉并結(jié)合熔滲工藝制備出不同顆粒(晶粒)尺寸的CuW70合金。運(yùn)用SEM、高溫蠕變實(shí)驗(yàn)、模擬高壓電弧燒蝕實(shí)驗(yàn)等探討了顆粒尺寸對(duì)鎢銅合金組織結(jié)構(gòu)與相關(guān)性能的影響,同時(shí)利用第一性原理分析計(jì)算了不同顆粒尺寸CuW70合金的場(chǎng)發(fā)射電子能力,探討了細(xì)晶鎢銅合金耐電弧燒蝕性的電擊穿機(jī)理。研究結(jié)果表明:(1)室溫下,鎢銅合金硬度和抗壓強(qiáng)度隨顆粒尺寸的增大而減小,電導(dǎo)率則隨顆粒尺寸的增大而升高,當(dāng)顆粒尺寸由0.52 μtm變?yōu)?0.69 μm時(shí),相對(duì)密度、硬度、抗壓強(qiáng)度、電導(dǎo)率分別從 99.2 %、202 HB、1232.17 MPa、42.8 %IACS 變化為 97.5 %、179 HB、1116.31 MPa、44.6 %IACS;而高溫下,粗晶粒的鎢銅合金表現(xiàn)出良好的抗蠕變性能,隨顆粒尺寸的減小合金的蠕變壽命變短,顆粒尺寸由0.52 μm變化到20.69 μuμm時(shí),合金蠕變壽命由26.3 h提高到87.2 h。(2)室溫下,試樣的斷口形貌為典型的解理斷口形貌特征,斷口以W-Cu界面斷裂和W-W界面斷裂為主;高溫下,材料內(nèi)部加熱溫度過(guò)高,削弱了鎢相和粘結(jié)相銅的界面結(jié)合強(qiáng)度,同時(shí),銅相斷裂時(shí)所需剪切應(yīng)力較鎢相低,故裂紋容易在兩相界面和銅相上產(chǎn)生,最終斷口以W-Cu界面斷裂和銅相延性斷裂為主。.(3)同一擊穿電壓下,細(xì)晶鎢銅合金相對(duì)于粗晶的首擊穿燒蝕面積大,擊穿坑多而淺,100次電擊穿后,表面均有銅的飛濺沉積,出現(xiàn)大量的孔洞和裸露的鎢骨架,顆粒越粗該現(xiàn)象越明顯。細(xì)晶銅相分散,散熱快,燒蝕面積大,燒蝕比較緩和;而粗晶合金銅相相對(duì)集中,燒蝕在此區(qū)域集中進(jìn)行,最終導(dǎo)致銅相大量損失,燒蝕嚴(yán)重。(4)細(xì)晶比粗晶更耐電弧燒蝕,其機(jī)理一是細(xì)晶鎢銅合金中銅相分布細(xì)小均勻,電弧不會(huì)在富銅區(qū)域聚集,而是均勻分布在陰極材料表面;二是細(xì)晶鎢銅合金中W骨架致密,微小的銅滴可嵌在鎢骨架中,使多次擊穿后合金表面仍保持光滑平整,微凸起引發(fā)的場(chǎng)致電子發(fā)射幾率減小,利于提高陰極材料的電擊穿性能;三是細(xì)晶晶界的功函數(shù)降低,從而降低陰極溫度和材料的蒸發(fā),以此來(lái)減輕電弧燒蝕。(5)隨外加電場(chǎng)增大,鎢銅合金費(fèi)米能級(jí)處態(tài)密度增大,外電場(chǎng)從0.087 Ha變化到0.12 Ha,態(tài)密度值從199.62 Ha增加到244.01 Ha。細(xì)顆粒鎢銅合金耐電壓強(qiáng)度高故外加電場(chǎng)強(qiáng)度大,態(tài)密度表示單位能量范圍內(nèi)的電子數(shù),故細(xì)晶場(chǎng)發(fā)射電子能力強(qiáng)。細(xì)顆粒鎢銅合金耐電弧燒蝕原因:一是細(xì)顆粒鎢銅合金,鎢相和銅相的均勻分布使勢(shì)壘寬度變窄,電子易隧穿出固體表面,場(chǎng)發(fā)射電子能力強(qiáng);二是內(nèi)電場(chǎng)在鎢銅晶界處形成,電子在晶界處聚積,電擊穿容易在此發(fā)生,而細(xì)晶晶界較多,電子發(fā)射點(diǎn)在材料表面分散進(jìn)行,使得試樣燒蝕較輕。
[Abstract]:The tungsten-copper alloy is widely used in contact materials, electrode materials and aerospace-resistant materials because of its good conductivity, thermal conductivity, arc erosion resistance and resistance to fusion. It is well known that the coarse-grained material has good high-temperature performance, but the fine-grained tungsten-copper alloy has the advantages of dispersing arc and arc-resistance. The CuW70 alloy with different particle size (grain size) was prepared by using tungsten powder with different particle size and in combination with the infiltration process. The effect of particle size on the structure and related properties of the tungsten-copper alloy structure was discussed by means of SEM, high-temperature creep experiment and high-pressure arc ablation experiment. The first principle was used to analyze the field emission electron capability of the CuW70 alloy with different particle sizes. The electric breakdown mechanism of fine-grained tungsten-copper alloy is discussed. The results show that: (1) The hardness and compressive strength of the tungsten-copper alloy decreases with the increase of the particle size, and the conductivity increases with the increase of the particle size, and when the particle size is changed from 0.52. m to 20.69. m u.m, the relative density, hardness, compressive strength, The electrical conductivity changed from 99.2%, 202HB, 1232.17MPa, 42.8% IACS to 97.5%,179 HB, 1116.31 MPa and 44.6% IACS, respectively. The creep life of the alloy was increased from 26.3 h to 87.2 h when the particle size was changed from 0.52. m u.m to 20.69. m The internal heating temperature of the material is too high, the interface bonding strength of the tungsten phase and the bonding phase copper is weakened, and at the same time, when the copper phase is broken, the required shear stress is lower than that of the tungsten phase, so that the crack can be easily generated on the two-phase interface and the copper phase, and the final fracture is mainly caused by the fracture of the W-Cu interface and the ductile fracture of the copper. (3) Under the same breakdown voltage, the area of the fine-grained tungsten-copper alloy with respect to the first breakdown and ablation area of the coarse crystal is large, the breakdown pit is more and shallow, and after 100 times of electrical breakdown, the surface all has the splashing and deposition of copper, a large number of holes and a bare tungsten skeleton appear, and the more coarse the particles are. The fine-grained copper phase is dispersed, the heat dissipation is fast, the ablation area is large, the ablation is relatively mild, and the copper phase of the coarse-crystal alloy is relatively concentrated, and the ablation is concentrated in the region, so that the copper phase is greatly lost and the ablation is serious. (4) the fine crystal is more resistant to arc ablation than the coarse crystal, the mechanism is that the copper phase in the fine-grained tungsten-copper alloy is fine and uniform, the arc does not collect in the copper-rich region, but is uniformly distributed on the surface of the cathode material; the W-framework in the fine-grained tungsten-copper alloy is compact, and the tiny copper drops can be embedded in the tungsten skeleton, The surface of the alloy after multiple breakdown is still smooth and flat, the field electron emission probability caused by the micro-bump is reduced, and the electric breakdown performance of the cathode material is facilitated; and thirdly, the work function of the fine crystal grain boundary is reduced, so that the cathode temperature and the evaporation of the material are reduced, so that the arc ablation is reduced. (5) With the increase of the applied electric field, the state density of the Fermi level of the tungsten-copper alloy is increased, the external electric field changes from 0.087Ha to 0.12Ha, and the state density value is increased from 0.62Ha to 244.01 Ha. The fine-grain-tungsten-copper alloy has high voltage-resistant strength, and the applied electric field intensity is large, and the state density indicates the number of electrons in the unit energy range, so that the fine-grain field emission electronic capacity is strong. the reason for arc ablation of the fine-particle tungsten-copper alloy is that the uniform distribution of the fine-particle tungsten-copper alloy, the tungsten phase and the copper phase makes the width of the barrier narrow, the electrons are easily tunneled out of the solid surface, the field emission is strong, the second is that the internal electric field is formed at the grain boundary of the tungsten copper, and the electrons are accumulated at the grain boundary, The electrical breakdown is easy to take place, and the fine crystal cell is more, and the electron emission point is dispersed on the surface of the material, so that the ablation of the sample is light.
【學(xué)位授予單位】：西安理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG146.411
本文編號(hào)：2478408
[Abstract]:The tungsten-copper alloy is widely used in contact materials, electrode materials and aerospace-resistant materials because of its good conductivity, thermal conductivity, arc erosion resistance and resistance to fusion. It is well known that the coarse-grained material has good high-temperature performance, but the fine-grained tungsten-copper alloy has the advantages of dispersing arc and arc-resistance. The CuW70 alloy with different particle size (grain size) was prepared by using tungsten powder with different particle size and in combination with the infiltration process. The effect of particle size on the structure and related properties of the tungsten-copper alloy structure was discussed by means of SEM, high-temperature creep experiment and high-pressure arc ablation experiment. The first principle was used to analyze the field emission electron capability of the CuW70 alloy with different particle sizes. The electric breakdown mechanism of fine-grained tungsten-copper alloy is discussed. The results show that: (1) The hardness and compressive strength of the tungsten-copper alloy decreases with the increase of the particle size, and the conductivity increases with the increase of the particle size, and when the particle size is changed from 0.52. m to 20.69. m u.m, the relative density, hardness, compressive strength, The electrical conductivity changed from 99.2%, 202HB, 1232.17MPa, 42.8% IACS to 97.5%,179 HB, 1116.31 MPa and 44.6% IACS, respectively. The creep life of the alloy was increased from 26.3 h to 87.2 h when the particle size was changed from 0.52. m u.m to 20.69. m The internal heating temperature of the material is too high, the interface bonding strength of the tungsten phase and the bonding phase copper is weakened, and at the same time, when the copper phase is broken, the required shear stress is lower than that of the tungsten phase, so that the crack can be easily generated on the two-phase interface and the copper phase, and the final fracture is mainly caused by the fracture of the W-Cu interface and the ductile fracture of the copper. (3) Under the same breakdown voltage, the area of the fine-grained tungsten-copper alloy with respect to the first breakdown and ablation area of the coarse crystal is large, the breakdown pit is more and shallow, and after 100 times of electrical breakdown, the surface all has the splashing and deposition of copper, a large number of holes and a bare tungsten skeleton appear, and the more coarse the particles are. The fine-grained copper phase is dispersed, the heat dissipation is fast, the ablation area is large, the ablation is relatively mild, and the copper phase of the coarse-crystal alloy is relatively concentrated, and the ablation is concentrated in the region, so that the copper phase is greatly lost and the ablation is serious. (4) the fine crystal is more resistant to arc ablation than the coarse crystal, the mechanism is that the copper phase in the fine-grained tungsten-copper alloy is fine and uniform, the arc does not collect in the copper-rich region, but is uniformly distributed on the surface of the cathode material; the W-framework in the fine-grained tungsten-copper alloy is compact, and the tiny copper drops can be embedded in the tungsten skeleton, The surface of the alloy after multiple breakdown is still smooth and flat, the field electron emission probability caused by the micro-bump is reduced, and the electric breakdown performance of the cathode material is facilitated; and thirdly, the work function of the fine crystal grain boundary is reduced, so that the cathode temperature and the evaporation of the material are reduced, so that the arc ablation is reduced. (5) With the increase of the applied electric field, the state density of the Fermi level of the tungsten-copper alloy is increased, the external electric field changes from 0.087Ha to 0.12Ha, and the state density value is increased from 0.62Ha to 244.01 Ha. The fine-grain-tungsten-copper alloy has high voltage-resistant strength, and the applied electric field intensity is large, and the state density indicates the number of electrons in the unit energy range, so that the fine-grain field emission electronic capacity is strong. the reason for arc ablation of the fine-particle tungsten-copper alloy is that the uniform distribution of the fine-particle tungsten-copper alloy, the tungsten phase and the copper phase makes the width of the barrier narrow, the electrons are easily tunneled out of the solid surface, the field emission is strong, the second is that the internal electric field is formed at the grain boundary of the tungsten copper, and the electrons are accumulated at the grain boundary, The electrical breakdown is easy to take place, and the fine crystal cell is more, and the electron emission point is dispersed on the surface of the material, so that the ablation of the sample is light.
【學(xué)位授予單位】：西安理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG146.411
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 郭向沛;謝敬佩;王愛(ài)琴;王榮旗;吳文杰;;顆粒尺寸對(duì)SiCp/6061Al復(fù)合材料組織及性能的影響[J];河南科技大學(xué)學(xué)報(bào)(自然科學(xué)版);2015年06期
2 王新剛;張懷龍;李文靜;劉麗麗;時(shí)斌;楊志懋;;制備工藝對(duì)WCu30合金的顯微組織及抗電弧燒蝕性能的影響[J];稀有金屬材料與工程;2015年01期
3 黃麗枚;羅來(lái)馬;丁孝禹;羅廣南;昝祥;洪雨;吳玉程;;鎢銅復(fù)合材料的研究進(jìn)展[J];機(jī)械工程材料;2014年04期
4 劉超;吝楠;賀躍輝;王宇川;張翔;;添加粗晶WC對(duì)WC-Co硬質(zhì)合金組織與力學(xué)性能的影響[J];粉末冶金材料科學(xué)與工程;2014年01期
5 劉鋒;王慶娟;杜忠澤;王靜怡;;ECAP制備超細(xì)晶材料組織及其性能的研究進(jìn)展[J];兵器材料科學(xué)與工程;2013年04期
6 王愛(ài)琴;倪增磊;謝敬佩;;顆粒尺寸及分布均勻性對(duì)SiC/Al-30Si復(fù)合材料組織性能的影響[J];粉末冶金技術(shù);2013年01期
7 談軍;周張健;屈丹丹;鐘銘;葛昌純;;超細(xì)晶鎢及其復(fù)合材料的研究現(xiàn)狀[J];粉末冶金工業(yè);2012年03期
8 馮威;李玉龍;朱曉東;;鎢銅復(fù)合材料的制備與應(yīng)用[J];成都大學(xué)學(xué)報(bào)(自然科學(xué)版);2011年04期
9 張劉杰;劉祖銘;劉詠;劉峰;趙大鵬;劉東華;郭薇;;Fe_2O_3對(duì)粉末冶金鐵基合金組織和力學(xué)性能的影響[J];粉末冶金材料科學(xué)與工程;2011年04期
10 范景蓮;張驍;游峰;田家敏;;雙粒度配比鎢粉對(duì)W-10Cu復(fù)合材料致密化、組織與性能的影響[J];中南大學(xué)學(xué)報(bào)(自然科學(xué)版);2011年05期
相關(guān)博士學(xué)位論文 前1條
1 楊曉敏;Mg-Al基強(qiáng)化相及固溶體結(jié)構(gòu)和性能的第一性原理研究[D];中北大學(xué);2014年
相關(guān)碩士學(xué)位論文 前4條
1 翟東;鎢銅、鎢鉬合金高溫高壓性質(zhì)的第一性原理研究[D];北京化工大學(xué);2015年
2 張鴻雁;細(xì)晶W-Cu合金的制備及力學(xué)性能的研究[D];北京理工大學(xué);2015年
3 雒晗;球磨工藝對(duì)鎢銅復(fù)合粉及鎢銅合金影響研究[D];西華大學(xué);2007年
4 黃新;優(yōu)質(zhì)粗晶WC粉末及合金的研制[D];重慶大學(xué);2004年
，本文編號(hào)：2478408
本文鏈接：http://www.sikaile.net/kejilunwen/jiagonggongyi/2478408.html
最近更新
教材專著
