本文關(guān)鍵詞： 陶瓷型殼 強(qiáng)度 撓度 透氣性 界面穩(wěn)定性　出處：《沈陽理工大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：高溫合金鑄件質(zhì)量與所使用的陶瓷型殼性能密切相關(guān)。本文主要研究了陶瓷原料與型殼性能的關(guān)系。陶瓷原料主要涉及了高嶺土和剛玉兩種耐火原料和兩種硅溶膠粘結(jié)劑。型殼性能涉及強(qiáng)度、撓度、透氣性和界面穩(wěn)定性共四個(gè)方面。研究了不同條件下的型殼性能變化趨勢和陶瓷原料的物相組成隨溫度的演化規(guī)律、形成機(jī)理,探討了建立物相組成與型殼性能的關(guān)系,從而掌握影響型殼強(qiáng)度、撓度、透氣性、界面穩(wěn)定性的影響因素和變化規(guī)律。型殼試樣所使用的關(guān)鍵材料有:FSIII快干型硅溶膠(簡稱F硅溶膠)和GS30普通硅溶膠(簡稱G硅溶膠)兩種粘結(jié)劑和EC95粉、硅酸鋯粉、剛玉砂、煤系(1#)和非煤系(2#)高嶺土五種耐火材料。利用XRD、DTA分析了高嶺土的物相組成;利用三點(diǎn)彎曲法和高溫自重變形法測定了型殼的抗折強(qiáng)度和撓度,通過XRD和SEM等方法研究了型殼的物相組成和顯微結(jié)構(gòu);利用高溫透氣性設(shè)備對精鑄型殼在不同溫度下的透氣性進(jìn)行了分析;實(shí)驗(yàn)還研究了多種耐火材料粉末及型殼面層與高溫合金的界面反應(yīng)情況。(1)高嶺土原料中出現(xiàn)了方石英、莫來石、石英相和石英玻璃相,但是在兩種高嶺土中的含量不盡相同。與常溫強(qiáng)度相比,兩種高嶺土型殼的高溫強(qiáng)度均有顯著提高。在高溫下,型殼內(nèi)出現(xiàn)了石英玻璃的晶化轉(zhuǎn)變、方石英轉(zhuǎn)變以及莫來石化反應(yīng),但不同型殼體系的相變規(guī)律不同。FSIII和GS30兩種硅溶膠對型殼強(qiáng)度的影響不大。這是因?yàn)?與原料中的方石英相比,石英玻璃對莫來石的形成有促進(jìn)作用,進(jìn)而提高型殼的高溫強(qiáng)度而減小潰散強(qiáng)度。(2)高嶺土型殼在1500℃及以上的溫度下高溫蠕變急劇增加,而EC95型殼在1000-1600℃的溫度范圍內(nèi)變形量上升較為平緩;燒結(jié)后高嶺土型殼會(huì)向背層方向而非沿重力方向彎曲直至斷裂。有機(jī)物提高了高嶺土型殼的蠕變變形,但對EC95型殼的影響不明顯。這是因?yàn)楦邘X土型殼與重力相反的蠕變變形由剛玉層與高嶺土層的熱膨脹不匹配導(dǎo)致,且石英玻璃含量越多則高嶺土層的膨脹量越大。EC95型殼的變形是由于型殼中石英玻璃的粘性流動(dòng)所致。(3)在1000-1400℃時(shí),高溫透氣性隨溫度升高而穩(wěn)定上升,但耐火材料對型殼透氣性的影響不大;在1400℃以上的溫度時(shí),高嶺土型殼的透氣性顯著升高;隨著試驗(yàn)溫度的升高,EC95型殼的透氣性上升速率先快后慢。無定形二氧化硅可以轉(zhuǎn)變?yōu)榉绞⒒蚺cEC95粉反應(yīng)生成莫來石。(4)氧化釔、鋁酸鈷和剛玉粉末與417G合金界面反應(yīng)嚴(yán)重。碳化硅和煤系高嶺土不適用于配置型殼面層漿料。EC95粉與硅酸鋯均與合金發(fā)生輕微的界面反應(yīng),合金與EC95面層反應(yīng)容易產(chǎn)生機(jī)械粘砂,而與硅酸鋯面層的反應(yīng)則表現(xiàn)為化學(xué)粘砂。
[Abstract]:The quality of superalloy castings is closely related to the properties of ceramic shell used. The relationship between ceramic raw materials and shell properties is studied in this paper. The ceramic raw materials mainly involve two kinds of refractory materials, kaolin and corundum, and two kinds of silicon solution. Adhesives. Properties of moulded shells, relating to strength, Four aspects, deflection, permeability and interfacial stability, are studied in this paper. The changing trend of shell properties under different conditions, the evolution law of phase composition of ceramic raw materials with temperature, the formation mechanism, and the relationship between the phase composition of the molded shell and the properties of the shell are discussed. In order to master the impact of the shell strength, deflection, air permeability, The key materials used in the mold shell samples include two kinds of binders: FSIII fast dry silica sol (F silica sol) and GS30 common silica sol (G silica sol) and EC95 powder, zirconium silicate powder, corundum sand, etc. The phase composition of kaolin was analyzed by XRDX DTA, and the flexural strength and deflection of the shell were measured by three point bending method and high temperature autogravity deformation method. The phase composition and microstructure of the mold shell were studied by XRD and SEM, and the permeability of the die casting shell at different temperatures was analyzed by means of high temperature gas permeability equipment. The interfacial reaction between the powder and shell layer of various refractories and superalloy was also studied. (1) the raw materials of kaolin, such as cristobalite, mullite, quartz and quartz glass phase, were found in the raw materials of kaolinite, such as quartz, mullite, quartz and glass. However, the content of kaolin in the two kinds of kaolin is different. Compared with the normal temperature strength, the high temperature strength of the two kinds of kaolinite molded shell is obviously improved. At high temperature, the quartz glass crystallizes in the mold shell. The change of cristobalite and mullite reaction, but the phase transition law of different shell system is different. FSIII and GS30 silica sol have little effect on the strength of molded shell, this is because compared with the cristobalite in raw material, Quartz glass can promote the formation of mullite, thus increasing the high temperature strength of the shell and decreasing the collapsing strength.) the high temperature creep of the kaolinite shell increases sharply at 1500 鈩，

本文編號(hào)：1526253