發(fā)布時(shí)間：2018-05-19 14:26

  本文選題：凝膠注模 + 鈦合金��； 參考：《北京科技大學(xué)》2015年博士論文

【摘要】：鈦合金具有密度低、比強(qiáng)度高、耐熱性強(qiáng)、耐蝕性好等優(yōu)異性能,被譽(yù)為“21世紀(jì)的金屬”,是極具發(fā)展前景的結(jié)構(gòu)材料。鈦及其合金不僅在航空航天領(lǐng)域有著十分重要的應(yīng)用,在化工、石油、輕工、冶金、醫(yī)學(xué)、體育、民用等行業(yè)也有著廣闊的應(yīng)用前景。然而,由于鈦的生產(chǎn)成本較高,大大限制了它的應(yīng)用。因此,研發(fā)鈦產(chǎn)品新制備工藝,對(duì)降低成本和擴(kuò)大鈦的應(yīng)用范圍意義重大。 粉末冶金技術(shù)能夠滿(mǎn)足鈦合金低成本與高性能的雙重目標(biāo)。以開(kāi)發(fā)大尺寸復(fù)雜形狀鈦合金結(jié)構(gòu)件為目的,本課題提出利用凝膠注模成形制備鈦合金。針對(duì)粉末鈦合金的控氧難題,從三方面展開(kāi)：在制粉方面,利化低氧氫化-脫氫工藝制備高純低氧氫化鈦及鈦粉；在成形方面,開(kāi)發(fā)無(wú)氧凝膠體系；在燒結(jié)方面,研究鎂、鈣、釹對(duì)致密化及氧的富集作用,結(jié)果如下： 利用氫化-脫氫工藝制備出100目、200目、325目、500目的氫化鈦及鈦粉產(chǎn)品。制粉過(guò)程中利用高純氫控制氫化過(guò)程的增氧、氮?dú)獗Ｗo(hù)控制破碎過(guò)程的增氧、高真空控制脫氫過(guò)程的增氧；且工序轉(zhuǎn)換時(shí)避免粉末與空氣接觸,獲得氧含量1000ppm的氫化鈦及鈦粉。 對(duì)比了氫化鈦及鈦粉的凝膠注模成形性能,氫化鈦及鈦粉固含量分別為50vol.%、37vol.%；經(jīng)1300°C燒結(jié)后,氫化鈦燒結(jié)相對(duì)密度95.9%,收縮率為22.5%,鈦粉燒結(jié)相對(duì)密度為92.5%,收縮率為20.8%,因而氫化鈦更適宜作為凝膠注模成形的原料。 針對(duì)常用聚合物凝膠體系氧殘留高的問(wèn)題,開(kāi)發(fā)無(wú)氧聚苯乙烯凝膠體系：1)在油酸含量0.55wt.%、苯乙烯含量50vol.%、固含量49vol.%的條件下,可得低粘度、高固含量的漿料；在二乙烯基苯含量40vol.%(苯乙烯含量10vol.%)、反應(yīng)溫度90℃、引發(fā)劑含量130mmol·L-1的條件下,固化時(shí)間約3.5h,坯體強(qiáng)度為20MPa；2)將低分子量有機(jī)凝膠成功引入到成形中,經(jīng)球磨后漿料固含量達(dá)51vol.%；凝膠溫度為40～45℃時(shí),固化時(shí)間為3～10min；聚苯乙烯濃度為0.08g·mL-1的條件下,坯體強(qiáng)度為10MPa。 聚苯乙烯體系的增氧及增碳量分別為0.07wt.%、0.2wt.%,低分子量有機(jī)凝膠體系的增氧及增碳量分別為0.1wt.%、0.16wt.%,利用該無(wú)氧體系成形出純鈦的抗拉強(qiáng)度510MPa、延伸率6.5%； 研究了鎂、鈣、釹對(duì)氫化鈦粉末燒結(jié)致密化及氧的影響,鎂、氫化鈣、釹均能促進(jìn)氫化鈦粉末的燒結(jié)致密化,在0.5wt.%Mg、0.375wt.%CaH2、0.5wt.%Nd的條件下,分別將燒結(jié)相對(duì)密度由96%提高到98.1%、98.2%、98.6%。由于密度的提高,添加鎂的樣品抗拉強(qiáng)度為538MPa、延伸率7.1%,得益于密度提高及氧的富集,Ti-0.375Ca樣品的抗拉強(qiáng)度為545MPa、延伸率9.2%, Ti-0.5Nd樣品的抗拉強(qiáng)度為590MPa、延伸率10.1%。 利用凝膠注模成形開(kāi)發(fā)出鈦門(mén)把手產(chǎn)品,成本約73元/kg,與傳統(tǒng)不銹鋼、銅合金、鋅鋁合金等材質(zhì)門(mén)把于相比,具有質(zhì)輕、美觀、生物相容性?xún)?yōu)異等特點(diǎn),易于宣傳推廣,市場(chǎng)前景廣闊,有望促進(jìn)鈦在民用領(lǐng)域的大范圍應(yīng)用。
[Abstract]:Titanium alloys with low density, high specific strength, strong heat resistance, good corrosion resistance and other excellent properties, known as "21 century metal", is a very promising structural materials. Titanium and its alloys not only have very important applications in the field of aerospace, but also have broad application prospects in chemical, petroleum, light industry, metallurgy, medicine, sports, civil and other industries. However, because of the high production cost of titanium, its application is greatly limited. Therefore, it is of great significance to develop a new preparation process for titanium products to reduce the cost and expand the application range of titanium. Powder metallurgy technology can meet the dual goals of low cost and high performance of titanium alloy. In order to develop large size and complex shape titanium alloy structural parts, this paper presents the preparation of titanium alloy by gel injection molding. Aiming at the problem of controlling oxygen in powder titanium alloy, the following three aspects are carried out: in the aspect of powder making, the preparation of high purity and low oxygen titanium hydride and titanium powder by using the technology of dehydrogenation and dehydrogenation of low oxygen, the development of anoxic gel system in forming, the study of magnesium and calcium in sintering, The effect of neodymium on densification and oxygen enrichment is as follows: Titanium hydride and titanium powder were prepared by hydrogenation-dehydrogenation process. High purity hydrogen is used to control the oxygenation in the hydrogenation process, nitrogen protection to control the oxygen increase in the breaking process, and high vacuum to control the oxygen increase in the dehydrogenation process, and to avoid the contact between the powder and the air during the process conversion, and to obtain titanium hydride and titanium oxide with oxygen content of 1000ppm. The gel injection molding properties of titanium hydride and titanium powder were compared. The solid content of titanium hydride and titanium powder were 50vol.37vol.0.After sintering at 1300 擄C, The relative density of titanium hydride sintering is 95.9, the shrinkage ratio is 22.5. the relative density of titanium powder sintering is 92.5 and the shrinkage rate is 20.8.The titanium hydride is more suitable as raw material for gel injection molding. Aiming at the problem of high oxygen residue in common polymer gel system, the low viscosity and high solid content slurry can be obtained under the conditions of oleic acid content 0.55 wt., styrene content 50 vol.and solid content 49vol.%. The low molecular weight organic gel was successfully introduced into the forming process under the conditions of the content of divinylbenzene (40 vol.% styrene, reaction temperature 90 鈩，

本文編號(hào)：1910455