本文選題：顆粒增強鈦基復合材料 + 緩進深切磨削　； 參考：《南京航空航天大學》2017年碩士論文

【摘要】：顆粒增強鈦基復合材料因具有高的比強度、比剛度以及優(yōu)異的高溫性能和耐蝕性能,在航空航天領(lǐng)域具有廣闊應(yīng)用前景。但是,由于該類材料中同時存在高強韌鈦合金基體和高硬脆增強顆粒這兩種力學性質(zhì)相差顯著的材料,使其成為了典型的難加工材料。采用普通切削和磨削加工存在加工效率低、工具壽命短、加工成本高、表面質(zhì)量差以及工件易燒傷等問題,嚴重制約了顆粒增強鈦基復合材料的加工質(zhì)量與效率,并阻礙了該材料的應(yīng)用進程。有鑒于此,本課題提出開展顆粒增強鈦基復合材料緩進深切磨削研究,通過三種剛玉砂輪緩進深切磨削鈦基復合材料的對比試驗研究,從磨削力與砂輪磨損、磨削溫度與熱量分配、加工表面完整性三個方面研究顆粒增強鈦基復材的磨削問題。研究成果對于實現(xiàn)顆粒增強鈦基復合材料高效精密加工具有重要理論意義和應(yīng)用價值。論文完成的主要研究工作及取得的成果如下:(1)揭示了剛玉砂輪緩進深切磨削顆粒增強鈦基復合材料磨削力與砂輪磨損的變化規(guī)律。磨削用量和砂輪種類對磨削力具有顯著影響,磨削力隨砂輪線速度增加而下降、隨工件進給速度與切深增大而上升。微晶剛玉砂輪的磨削力明顯小于白剛玉與鉻剛玉砂輪,這表明微晶陶瓷剛玉砂輪最鋒利。微晶剛玉砂輪緩進深切磨削顆粒增強鈦基復合材料過程中,砂輪磨損主要以粘附為主,并且隨著切深的增大,粘附面積逐漸增加。(2)研究了緩進深切磨削顆粒增強鈦基復合材料的磨削溫度與熱量分配比例。磨削溫度隨砂輪線速度和切深增大而升高,隨工件進給速度增大而減小。同等條件下,微晶剛玉砂輪的磨削溫度低于其它砂輪。緩進深切磨削過程中,磨削弧區(qū)冷卻液存在泡核沸騰和膜沸騰兩個階段。當切深小于0.6mm時,磨削弧區(qū)冷卻液處于泡核階段,冷卻作用顯著,磨削溫度變化比較平緩并且最高溫度小于130℃。然而,當切深大于0.8mm時,磨削熱量易使磨削弧區(qū)冷卻液從泡核階段轉(zhuǎn)變?yōu)槟し序v階段,磨削溫度升高至700℃以上,工件發(fā)生燒傷。泡核沸騰和膜沸騰階段,磨削熱量進入工件的比例分別為20~30%和70~85%。(3)探明了緩進深切磨削顆粒增強鈦基復合材料的加工表面完整性。緩進深切磨削表面形貌主要包括塑性切削方式去除鈦合金基材產(chǎn)生的涂覆、溝槽與裂紋,以及增強顆粒以拔出、破碎、壓入等方式去除產(chǎn)生的孔洞。同時,闡明了磨削用量對加工表層顯微硬度、金相組織以及殘余應(yīng)力的影響規(guī)律。由此,提出了優(yōu)化的緩進深切磨削工藝參數(shù)范圍。
[Abstract]:Because of its high specific strength, specific stiffness, excellent high temperature performance and corrosion resistance, particle reinforced titanium matrix composites have a wide application prospect in the field of aeronautics and astronautics. However, due to the existence of both high strength and tough titanium alloy matrix and high hard brittle reinforced particles, these two materials have different mechanical properties, which make them become typical refractory materials. The problems of low machining efficiency, short tool life, high machining cost, poor surface quality and easy burn of workpiece have seriously restricted the machining quality and efficiency of particle reinforced titanium matrix composites. It also hinders the application of the material. In view of this, this paper puts forward to carry out the research of progressive deep grinding of particle reinforced titanium matrix composites. Through the comparative experimental study of three kinds of corundum grinding wheels, the grinding force and grinding wheel wear are studied. Grinding temperature and heat distribution and surface integrity are studied in this paper. The research results have important theoretical significance and application value for realizing high efficiency precision machining of particle reinforced titanium matrix composites. The main research work and results obtained in this paper are as follows: 1) the variation of grinding force and wheel wear of grain reinforced titanium matrix composites by corundum grinding wheel is revealed. The grinding force decreases with the increase of the linear speed of the grinding wheel and increases with the increase of the feed speed and the cutting depth of the workpiece. The grinding force of microcrystalline corundum grinding wheel is obviously less than that of white corundum and chrome corundum grinding wheel, which indicates that the microcrystalline ceramic corundum grinding wheel is the sharpest. In the process of microcrystalline corundum wheel slowly advancing deep grinding particle reinforced titanium matrix composites, the wear of grinding wheel is mainly adhesion, and with the increase of cutting depth, The ratio of grinding temperature to heat distribution of grain reinforced titanium matrix composites with slowly advancing deep grinding was studied. The grinding temperature increases with the increase of grinding wheel linear velocity and cutting depth, and decreases with the increase of workpiece feed speed. Under the same conditions, the grinding temperature of microcrystalline corundum grinding wheel is lower than that of other grinding wheels. There are two stages of bubble nucleation boiling and film boiling in the coolant in the arc zone of the grinding process. When the cutting depth is less than 0.6mm, the coolant in the grinding arc zone is in the stage of bubble nucleus, the cooling effect is obvious, the grinding temperature changes slowly and the maximum temperature is less than 130 鈩，

本文編號：1995092