Please wait a minute...
金属学报  2018, Vol. 54 Issue (5): 824-830    DOI: 10.11900/0412.1961.2017.00312
  金属材料的凝固专刊 本期目录 | 过刊浏览 |
翟斌, 周凯, 吕鹏, 王海鹏()
西北工业大学应用物理系 西安 710072
Rapid Solidification of Ti-6Al-4V Alloy Micro-Droplets Under Free Fall Condition
Bin ZHAI, Kai ZHOU, Peng Lü, Haipeng WANG()
Department of Applied Physics, Northwestern Polytechnical University, Xi'an 710072, China
全文: PDF(7656 KB)   HTML

在自由落体条件下实现了Ti-6Al-4V合金微液滴的深过冷与快速凝固,研究了合金的相组成、凝固组织和显微硬度。计算出落管中不同直径微液滴的过冷度和冷却速率,揭示了Ti-6Al-4V合金凝固组织随过冷度及冷却速率的变化规律。结果表明,深过冷与快冷速的耦合作用使凝固组织不断细化且形貌发生转变:层片α+β→枝晶α→网篮状α'+β→针状α'→针状α'+不规则β。当液滴直径小于400 μm时,位于原始等轴β晶的晶界及晶内的针状马氏体α'转化为大量连续分布且形状不规则的次生β相,发生α'β固态转变。不同直径范围内的Ti-6Al-4V合金凝固组织的显微硬度与组织形貌有关,“层片组织”、“ 针状α'组织”和“针状α'+不规则β组织”的显微硬度随液滴直径的减小而增大,“网篮组织”的显微硬度随液滴直径的减小而减小。其中,枝晶组织的显微硬度可高达785 kg/mm2,是母合金硬度的2.6倍。

关键词 钛合金深过冷快速凝固微观组织显微硬度    

Especially in the past decades, Ti-6Al-4V alloy has received much attention, not only due to its high melting temperature, good corrosion resistance, low density and high hardness, but also because of the diverse and complicated microstructures formed under different conditions. This makes Ti-6Al-4V a potential candidate in both aerospace industries and fundamental research. It is well known that the solidified microstructures of alloy have a great influence on their mechanical properties. Therefore, it is crucial to investigate the mechanical properties of Ti-6Al-4V solidified under different conditions, in particular in the undercooling conditions. However, it is noted that most research on the solidification of Ti-6Al-4V alloy was carried out under equilibrium condition. With respect to Ti-6Al-4V alloy solidified under substantial undercooling conditions, few studies could be found. Thus, it is interesting to study two points: (1) the feature of the microstructure of Ti-6Al-4V alloy solidified under highly undercooled conditions and large cooling rate, (2) the influence of undercooling and cooling rate on the mechanical property of Ti-6Al-4V alloy. To address these two problems, Ti-6Al-4V alloy was rapidly solidified in a drop tube. The main results are summarized as follows. The microstructure of the Ti-6Al-4V alloy solidified under free fall condition displays "lamellar α+βα dendrites→basket-weave α'+β→ needle-like α'→ needle-like α'+ anomalous β " transformation with decreasing the droplets diameter. And the needle-like α' phase in the original boundaries of equiaxed β grains is transformed into a continuous distribution and anomalous structure of β phase when the droplet size is less than about 400 μm. The microhardness of this alloy ranges from 506 kg/mm2 to 785 kg/mm2 when the droplet diameter decreases from 1420 μm to 88 μm, which is much higher than that of the master alloy. For "lamellar structure of α+β phases", "needle-like α' phase" and "needle-like α' phase+ anomalous β phase", the microhardness increases with the decrease of droplet diameter. But for 'basket-weave' microstructure, the microhardness diminishes with the decrease of droplet diameter.

Key wordstitanium alloy    high undercooling    rapid solidification    microstructure    microhardness
收稿日期: 2017-07-25     
ZTFLH:  TG113.12  
基金资助:资助项目 国家自然科学基金项目Nos.51474175、51522102、51506182和51734008,以及航空科学基金项目No.2016ZF53060

作者简介 翟 斌,男,1993年生,硕士生


翟斌, 周凯, 吕鹏, 王海鹏. 自由落体条件下Ti-6Al-4V合金微液滴的快速凝固研究[J]. 金属学报, 2018, 54(5): 824-830.
Bin ZHAI, Kai ZHOU, Peng Lü, Haipeng WANG. Rapid Solidification of Ti-6Al-4V Alloy Micro-Droplets Under Free Fall Condition. Acta Metall Sin, 2018, 54(5): 824-830.

链接本文:      或

图1  Ti-6Al-4V母合金的XRD谱和DSC曲线
图2  Ti-6Al-4V合金微液滴过冷度与冷却速率随直径变化的曲线
图3  Ti-6Al-4V母合金典型凝固组织和直径D=1330 μm合金微液滴的凝固组织
图4  不同直径Ti-6Al-4V合金微液滴的凝固组织
图5  Ti-6Al-4V合金β相含量与液滴直径的关系
图6  Ti-6Al-4V合金微液滴凝固组织显微硬度与直径的关系
[1] Devaraj A, Joshi V V, Srivastava A, et al.A low-cost hierarchical nanostructured beta-titanium alloy with high strength[J]. Nat. Commun., 2016, 7: 11176
[2] Zou P F, Wang H P, Yang S J, et al.Anomalous temperature dependence of liquid state density for Ni50Ti50 alloy investigated under electrostatic levitation state[J]. Chem. Phys. Lett., 2017, 681: 101
[3] Zhang S Z, Li C, Hou W T, et al.Longitudinal compression behavior of functionally graded Ti-6Al-4V meshes[J]. J. Mater. Sci. Technol., 2016, 32: 1098
[4] Zhao Z, Chen J, Guo S, et al.Influence of α/β interface phase on the tensile properties of laser cladding deposited Ti-6Al-4V titanium alloy[J]. J. Mater. Sci. Technol., 2017, 33: 675
[5] Liu H H, Niinomi M, Nakai M, et al.β-type titanium alloys for spinal fixation surgery with high Young's modulus variability and good mechanical properties[J]. Acta Biomater., 2015, 24: 361
[6] Kobryn P A, Moore E H, Semiatin S L.The effect of laser power and traverse speed on microstructure, porosity, and build height in laser-deposited Ti-6Al-4V[J]. Scr. Mater., 2000, 43: 299
[7] Thijs L, Verhaeghe F, Craeghs T, et al.A study of the microstructural evolution during selective laser melting of Ti-6Al-4V[J]. Acta Mater., 2010, 58: 3303
[8] Vrancken B, Thijs L, Kruth J P, et al.Heat treatment of Ti6Al4V produced by Selective Laser Melting: Microstructure and mechanical properties[J]. J. Alloys Compd., 2012, 541: 177
[9] He T, Hu R, Zhang T B, et al.Effect of Nb content on solidification characteristics and microsegregation in cast Ti-48Al-xNb alloys[J]. Acta Metall. Sin.(Engl. Lett.), 2016, 29: 714
[10] Liu Y, Hu R, Zhang T B, et al.Dendritic growth and microstructure evolution with different cooling rates in Ti-48Al-2Cr-2Nb alloy[J]. J. Mater. Eng. Perform., 2016, 25: 38
[11] Zhou K, Wei B.Determination of the thermophysical properties of liquid and solid Ti-6Al-4V alloy[J]. Appl. Phys., 2016, 122A: 248
[12] Wang H Y, Liu R P, Zhan Z J, et al.Dynamic and thermal computation of Fe-66.7%Si droplets free falling in a drop tube[J]. Acta Metall. Sin., 2005, 41: 940(王海燕, 刘日平, 战再吉等. Fe-66.7%Si合金液滴落管实验的动力学和传热学计算[J]. 金属学报, 2005, 41: 940)
[13] Oloyede O, Bigg T D, Cochrane R F, et al.Microstructure evolution and mechanical properties of drop-tube processed, rapidly solidified grey cast iron[J]. Mater. Sci. Eng., 2016, A654: 143
[14] Luo S B, Wang W L, Xia Z C, et al.Theoretical prediction and experimental observation for microstructural evolution of undercooled nickel-titanium eutectic type alloys[J]. J. Alloys Compd., 2017, 692: 265
[15] Wang G Q, Zhao Z B, Yu B B, et al.Effect of base material on microstructure and texture evolution of a Ti-6Al-4V electron-beam welded joint[J]. Acta Metall. Sin.(Engl. Lett.), 2017, 30: 499
[16] Broderick T F, Jackson A G, Jones H, et al.The effect of cooling conditions on the microstructure of rapidly solidified Ti-6Al-4V[J]. Metall. Mater. Trans., 1985, 16: 1951
[17] Ding R, Guo Z X, Wilson A.Microstructural evolution of a Ti-6Al-4V alloy during thermomechanical processing[J]. Mater. Sci. Eng., 2002, A327: 233
[18] Grant P S, Cantor B, Katgerman L.Modelling of droplet dynamic and thermal histories during spray forming—I. Individual droplet behavior[J]. Acta Metall. Mater., 1993, 41: 3097
[19] Lee E S, Ahn S.Solidification progress and heat transfer analysis of gas-atomized alloy droplets during spray forming[J]. Acta Metall. Mater., 1994, 42: 3231
[20] Xu Z Y.Martensitic Transformation and Martensite [M]. Beijing: Science Press, 1980: 29(徐祖耀. 马氏体相变与马氏体 [M]. 北京: 科学出版社, 1980: 29)
[21] Ramirez-Ledesma A L, Lopez-Molina E, Lopez H F, et al. Athermal ε-martensite transformation in a Co-20Cr alloy: Effect of rapid solidification on plate nucleation[J]. Acta Mater., 2016, 111: 138
[22] Ahmed T, Rack H J.Phase transformations during cooling in α+β titanium alloys[J]. Mater. Sci. Eng., 1998, A243: 206
[23] Peng X N, Guo H Z, Wang T, et al.Effects of β treatments on microstructures and mechanical properties of TC4-DT titanium alloy[J]. Mater. Sci. Eng., 2012, A533: 55
[24] Hrabe N, Quinn T.Effects of processing on microstructure and mechanical properties of a titanium alloy (Ti-6Al-4V) fabricated using electron beam melting (EBM), Part 2: Energy input, orientation, and location[J]. Mater. Sci. Eng., 2013, A573: 271
[25] Wu S Q, Lu Y J, Gan Y L, et al.Microstructural evolution and microhardness of a selective-laser-melted Ti-6Al-4V alloy after post heat treatments[J]. J. Alloys Compd., 2016, 672: 643
[26] Wang L, Su Y Q, Wang S J, et al.Effect of melt hydrogenation on structure and hardness of TC21 alloy[J]. Rare Met. Mater. Eng., 2011, 40: 321(王亮, 苏彦庆, 王书杰等. 液态置氢对TC21合金组织及硬度的影响[J]. 稀有金属材料与工程, 2011, 40: 321)
[1] 刘震鹏, 闫志巧, 陈峰, 王顺成, 龙莹, 吴益雄. 金刚石工具用Cu-10Sn-xNi合金的制备和性能表征[J]. 金属学报, 2020, 56(5): 760-768.
[2] 赵燕春, 毛雪晶, 李文生, 孙浩, 李春玲, 赵鹏彪, 寇生中. Fe-15Mn-5Si-14Cr-0.2C非晶钢微观组织与腐蚀行为[J]. 金属学报, 2020, 56(5): 715-722.
[3] 柯林达,殷杰,朱海红,彭刚勇,孙京丽,陈昌棚,王国庆,李中权,曾晓雁. 钛合金薄壁件选区激光熔化应力演变的数值模拟[J]. 金属学报, 2020, 56(3): 374-384.
[4] 程超,陈志勇,秦绪山,刘建荣,王清江. TA32钛合金厚板的微观组织、织构与力学性能[J]. 金属学报, 2020, 56(2): 193-202.
[5] 邓聪坤,江鸿翔,赵九洲,何杰,赵雷. Ag-Ni偏晶合金凝固过程研究[J]. 金属学报, 2020, 56(2): 212-220.
[6] 马晋遥,王晋,赵云松,张剑,张跃飞,李吉学,张泽. 一种第二代镍基单晶高温合金1150 ℃原位拉伸断裂机制研究[J]. 金属学报, 2019, 55(8): 987-996.
[7] 李学雄,徐东生,杨锐. 双相钛合金高温变形协调性的CPFEM研究[J]. 金属学报, 2019, 55(7): 928-938.
[8] 杜随更,高漫,徐婉婷,王喜锋. TC11/TC17钛合金线性摩擦焊接头界面研究[J]. 金属学报, 2019, 55(7): 885-892.
[9] 黄森森,马英杰,张仕林,齐敏,雷家峰,宗亚平,杨锐. α+β两相钛合金元素再分配行为及其对显微组织和力学性能的影响[J]. 金属学报, 2019, 55(6): 741-750.
[10] 任德春, 苏虎虎, 张慧博, 王健, 金伟, 杨锐. 冷旋锻变形对TB9钛合金显微组织和拉伸性能的影响[J]. 金属学报, 2019, 55(4): 480-488.
[11] 许擎栋, 李克俭, 蔡志鹏, 吴瑶. 脉冲磁场对TC4钛合金微观结构的影响及其机理探究[J]. 金属学报, 2019, 55(4): 489-495.
[12] 刘耀鸿,王朝辉,刘轲,李淑波,杜文博. Er对Mg-5Zn-xEr镁合金热裂敏感性的影响[J]. 金属学报, 2019, 55(3): 389-398.
[13] 邵成伟, 惠卫军, 张永健, 赵晓丽, 翁宇庆. 一种新型高强度高塑性冷轧中锰钢的组织和力学性能[J]. 金属学报, 2019, 55(2): 191-201.
[14] 田银宝, 申俊琦, 胡绳荪, 勾健. 丝材+电弧增材制造钛/铝异种金属反应层的研究[J]. 金属学报, 2019, 55(11): 1407-1416.
[15] 何波, 邢盟, 杨光, 邢飞, 刘祥宇. 成分梯度对激光沉积制造TC4/TC11连接界面组织和性能的影响[J]. 金属学报, 2019, 55(10): 1251-1259.