1. 毕业设计（论文）的内容和要求

钛合金的性能与显微组织特征密切相关，钛合金组织特征强烈依赖于其热处理参数，而合金的组织演变又取决于合金在热处理过程中复杂多样的相变过程，不同的热处理参数会使合金中相的种类、数量、形貌、尺寸、分布等不同，从而引起性能的变化，了解和掌握钛合金中的相变规律，运用这些规律调整热处理工艺参数来改变合金组织，从而挖掘合金的性能潜力是极为重要的，并且对于新型钛合金的设计和开发具有重要的指导意义。

本课题通过连续升温和冷却热膨胀法(dil)研究tc4-f合金在冷却过程中的α相析出过程的相变行为和显微组织演化。

通过kissinger-akahira-sunose（kas）方法得到α相转变平均相变激活能e；同时通过kolmogorov-johnson-mehl-avrami(kjma)模型计算出随着α相体积的增大所对应的avrami指数n，并分析对应的相变机制。

2. 参考文献

[1] 陈国琳, 吴鹏炜, 冷文军, 等. 钛合金的发展现状及应用前景[J]. 舰船科学技术, 2009, 31(12): 110-113. [2] 舒群, 郭永良, 陈子勇, 等. 铸造钛合金及其熔炼技术的发展现状[J]. 材料科学与工艺, 2004, 12(3): 332-336. [3] 王蕊宁, 杨建朝, 吕利强, 等. 不同热处理工艺对工业TC4合金板材组织和性能的影响[J]. 钛工业进展, 2010, 27(6): 27-29. [4] Guo P, Zhao Y, Zeng W, et al. The effect of microstructure on the mechanical properties of TC4-DT titanium alloys [J]. Materials Science Engineering A, 2013, 563(2): 106-111. [5] 宋西平. 钛合金在汽车零件上的应用现状及研发趋势[J]. 钛工业进展, 2007, 24(5): 9-13. [6] Ahmed M, Li T, Casillas G, et al. The evolution of microstructure and mechanical properties of Ti#8211;5Al#8211;5Mo#8211;5V#8211;2Cr#8211;1Fe during ageing[J]. Journal of Alloys Compounds, 2015, 629: 260-273. [7] Doraiswamy D, Ankem S. The effect of grain size and stability on ambient temperature tensile and creep deformation in metastable beta titanium alloys [J]. Acta Materialia, 2003, 51(6): 1607-1619. [8] Chesnutt J C, Froes F H. Effect of α-phase morphology and distribution on the tensile ductility of a metastable beta titanium alloy[J]. Metallurgical Transactions A, 1977, 8(6): 1013-1017. [9] Makino T, Chikaizumi R, Nagaoka T, et al. Microstructure development in a thermomechanically processed Ti15V3Cr3Sn3Al alloy[J]. Materials Science Engineering A, 1996, 213(s 1-2): 51-60. [10] Froesf H, Yolton C F, Capenos J M, et al. The relationship between microstructure and age hardening response in the metastable beta titanium alloy Ti- 11.5Mo-6Zr-4.5Sn (beta III)[J]. Metallurgical Materials Transactions A, 1980, 11(1): 21-31. [11] 徐洲, 赵连城. 金属固态相变原理[M]. 北京科学出版社, 2004. [12] Teter D F, Robertson I M, Birnbaum H K. The effects of hydrogen on the deformation and fracture of -titanium[J]. Acta Materialia, 2001, 49(20): 4313-4323. [13] Ahmed M, Savvakin D G, Ivasishin O M, et al. Microstructure evolution and alloying elements distribution between the phases in powder near-β titanium alloys during thermo-mechanical processing[J]. Journal of Materials Science, 2012, 47(19): 7013-7025. [14] 武宏让. 航空用钛合金[J]. 钛工业进展, 2000, 2: 30-31. [15] 王世洪, 沈桂琴, 梁佑明. Ti-15V-3Cr-3Sn-3Al合金中的相变研究[J]. 材料工程, 1992, ( s1): 175-177. [16] Furuhara T, Maki T, Makino T. Microstructure control by thermomechanical processing in β-Ti#8211;15#8211;3 alloy[J]. Journal of Materials Processing Technology, 2001, 117(3): 318-323. [17] Rhodes C G, Williams J C. The precipitation of α-phase in metastable β -phase Ti alloys [J]. Metallurgical Transactions A, 1975, 6(11): 2103-2114. [18] Chen W, Yao S, Liu R, et al. Phase Transformation Behavior and Mechanical Properties of Ti-10V-2Fe-3Al Alloy Subjected to Low Temperature Aging[J]. Rare Metal Materials Engineering, 2016, 7: 1726-1731. [19] 徐洲, 赵连城. 高等院校教材:金属固态相变原理[M]. 科学出版社, 2004. [20] 肖纪美. 合金相与相变[M]. 冶金工业出版社, 2004. [21] 冯端. 金属物理学.第二卷,相变[M]. 北京科学出版社, 2000. [22] Christian J W, Otte H M. The Theory of Transformations in Metals and Alloys[M]. Pergamon Press, 1965. [23] Malinov S, Sha W. Application of artificial neural networks for modelling correlations in titanium alloys[J]. Materials Science Engineering A, 2004, 365(1): 202-211. [24] Malinov S, Sha W. Modeling thermodynamics, kinetics, and phase transformation morphology while heat treating titanium alloys [J]. JOM, 2005, 57(9): 42-45. [25] Wang Y Z, Ma N, Chen Q, et al. Predicting phase equilibrium, phase transformation, and microstructure evolution in titanium alloys[J]. JOM, 2005, 57(9): 32-39. [26] Malinov S, Markovsky P, Sha W. Resistivity study and computer modelling of the isothermal transformation kinetics of Ti#8211;8Al#8211;1Mo#8211;1V alloy[J]. Journal of Alloys Compounds, 2002, 333(1): 122-132. [27] Malinov S, Sha W, Guo Z, et al. Synchrotron X-ray diffraction study of the phase transformations in titanium alloys[J]. Materials Characterization, 2001, 48(4): 279-295.

3. 毕业设计（论文）进程安排

2018.12.24-2019.3.1 查阅文献，完成外文翻译，完成开题报告。

2019.3.2-2019.3.22 制定实验研究方案，确定冷却速率，了解熟悉实验相关设备并学习如何使用热膨胀分析仪。

2019.3.23-2019.4.26 进行合金热处理及不同冷速的膨胀实验，获得热膨胀实验数据得到β转变为α相转变曲线，建立cct图并进行微观组织分析。