本文選題：原位自生TiB+TiC + 馬氏體相變��； 參考：《哈爾濱工業(yè)大學(xué)》2017年碩士論文

【摘要】：Ti-V-Al合金是一種在航天方面極具潛力的形狀記憶合金。目前Ti-V-Al形狀記憶合金彈性模量低,用于武器裝備中復(fù)合材料結(jié)構(gòu)連接時在低負(fù)載情況下易出現(xiàn)連接失效問題,限制了Ti-V-Al輕質(zhì)記憶合金連接緊固件在航天器連接結(jié)構(gòu)中的應(yīng)用。本文借鑒了復(fù)合材料的思路,通過原位自生的方式向Ti-13V-3Al合金中引入了增強(qiáng)相以提高合金的彈性模量與屈服強(qiáng)度。論文系統(tǒng)研究了不同增強(qiáng)相類別及體積分?jǐn)?shù)的復(fù)相Ti-V-Al記憶合金的組織結(jié)構(gòu)、馬氏體相變及其熱循環(huán)穩(wěn)定性、力學(xué)性能和形狀記憶效應(yīng)。通過熱力學(xué)計算可以得出Ti-TiB_2體系在合金中引入的增強(qiáng)相為TiB、Ti-B4C體系在合金中引入的增強(qiáng)相為TiB、TiC。固溶態(tài)復(fù)相Ti-V-Al記憶合金的室溫組織為α"馬氏體與增強(qiáng)相組成。增強(qiáng)相的引入細(xì)化了合金晶粒,TiB在合金中多為纖維狀,一部分為顆粒狀,TiC在合金中為顆粒狀。隨著增強(qiáng)相體積分?jǐn)?shù)增加,TiC的數(shù)量和尺寸隨之增大,顆粒狀TiB的數(shù)量隨之增大,在體積分?jǐn)?shù)為0.5%~5%時,纖維狀TiB的長徑比先增大后減小,在體積分?jǐn)?shù)為1%時達(dá)到最大。隨著增強(qiáng)相的引入,復(fù)相Ti-V-Al記憶合金馬氏體逆相變溫度升高、熱穩(wěn)定性提高。增強(qiáng)相體積分?jǐn)?shù)增加,固溶態(tài)復(fù)相Ti-V-Al記憶合金馬氏體逆相變溫度Ap升高。以Ti-B4C體系添加增強(qiáng)相對于合金熱穩(wěn)定性的提高要強(qiáng)于Ti-TiB_2體系。當(dāng)增強(qiáng)相體積分?jǐn)?shù)增加為0.5%時,合金的馬氏體熱穩(wěn)定性最好。增強(qiáng)相體積分?jǐn)?shù)為0.5%時,TiB與TiC共同作為增強(qiáng)相的強(qiáng)化效果要好于TiB單一增強(qiáng)相的強(qiáng)化效果。隨著增強(qiáng)相體積分?jǐn)?shù)的增加,合金的延伸率逐漸下降,彈性模量與屈服強(qiáng)度逐漸上升,抗拉強(qiáng)度先增大后減小。合金在增強(qiáng)相體積分?jǐn)?shù)為0.5%時綜合力學(xué)性能最佳。隨著增強(qiáng)體體積分?jǐn)?shù)的增加,合金的記憶效應(yīng)先增大后減少,在增強(qiáng)體體積分?jǐn)?shù)為1%時達(dá)到最大。
[Abstract]:Ti-V-Al alloy is a shape memory alloy with great potential in spaceflight. Due to the low elastic modulus of Ti-V-Al shape memory alloy (SMA), the connection failure of Ti-V-Al shape memory alloy (SMA) is easy to occur in the case of low load, which limits the application of Ti-V-Al light memory alloy fastener in spacecrafts. In order to improve the elastic modulus and yield strength of Ti-13V-3Al alloy, the reinforcement phase was introduced into Ti-13V-3Al alloy in situ by using the idea of composite material. The microstructure, martensitic transformation and thermal cycling stability, mechanical properties and shape memory effect of multiphase Ti-V-Al memory alloy with different reinforcement phases and volume fraction were systematically studied in this paper. The thermodynamics calculation shows that the reinforcement phase introduced in Ti-TiB _ 2 system is TiB- Ti-B4C system, and the reinforcement phase is TiB-B4C system. The room temperature microstructure of solid solution multiphase Ti-V-Al memory alloy is composed of 偽 "martensite and reinforcement phase." With the introduction of the reinforcing phase, the grain size of TIB in the alloy is mostly fibrous, and some of the TIB is granular in the alloy. With the increase of the volume fraction of reinforcing phase, the number and size of tic increase, and the number of granular TIB increases. When the volume fraction is 0.5 ~ 5, the aspect ratio of fibrous TIB increases first and then decreases, and reaches the maximum when the volume fraction is 1. With the introduction of the reinforcing phase, the reverse transformation temperature of martensite and the thermal stability of the multiphase Ti-V-Al memory alloy are increased. The increase of volume fraction of reinforcing phase increases the temperature of inverse transformation of martensite in solid solution Ti-V-Al memory alloy. The increase of thermal stability of Ti-B4C system is stronger than that of Ti-TiB-2 system. When the volume fraction of reinforcing phase is increased to 0.5, the thermal stability of martensite is the best. When the volume fraction of reinforcing phase is 0.5, the strengthening effect of TIB and tic as reinforcing phase is better than that of TIB single reinforcing phase. With the increase of the volume fraction of the reinforced phase, the elongation of the alloy decreases gradually, the elastic modulus and yield strength increase gradually, and the tensile strength increases first and then decreases. The alloy has the best comprehensive mechanical properties when the volume fraction of reinforcing phase is 0.5. With the increase of the volume fraction of the reinforcements, the memory effect of the alloy first increases and then decreases, and reaches the maximum when the volume fraction of the reinforcements is 1.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG139.6
，

本文編號：2080468