Optimization of heat treatment process for Ti551 titanium alloy based on phase transformation regulation
-
摘要: 利用光学显微镜、扫描电镜与万能拉伸机，研究了固溶温度、时效温度及冷却速度对Ti551合金组织与力学性能的影响。固溶温度900 ℃时，550～650 ℃时效温度升高对初生α相无明显变化，次生α相片层厚度从0.26 μm增至0.42 μm；时效温度550 ℃时，900～950 ℃固溶温度升高让初生α相含量从45%降至15%，尺寸细化且形貌由短棒状转为等轴状，次生α相增厚至0.72 μm。冷却速度对合金组织起决定性调控作用，炉冷形成单一等轴初生α相组织，中等冷却速度则细化初生α相并促进粗大片层次生α相析出。研究表明，900 ℃×2 h空冷+550 ℃×6 h时效的热处理工艺可使Ti551合金获得最优强韧性匹配，较快冷却速度促使β组织生成细针状次生α相，经后续时效进一步强化了合金的强塑性匹配效果。Abstract: The effects of heat treatment parameters including solution temperature, aging temperature and cooling rate on the microstructure and mechanical properties of a new medium-strength and high-toughness Ti551 alloy were investigated by means of optical microscopy, scanning electron microscopy and universal tensile testing machine. With the same solid solution temperature at 900 ℃, no obvious changes were observed in the content and size of primary α phase of alloy, while the lamellar thickness of secondary α phase increased from 0.26 μm to 0.42 μm with the aging temperature increasing from 550 ℃ to 650 ℃. With the same aging temperature of 550 ℃, the content of the primary α phase decreased from 45% to 15% as the solution temperature increased from 900 ℃ to 950 ℃, along with continuous refinement of grains and morphological transformation from short rod-like to equiaxed. The lamellar thickness of the secondary α phase increased accordingly, reaching up to 0.72 μm after alloy subject to solid solution treatment at 950 ℃. The morphological feature and size of the microstructure are decisively influenced by the cooling rate: an almost single fully equiaxed primary α phase microstructure is obtained by furnace cooling, whereas the primary α phase is refined and the precipitation of coarse lamellar secondary α phase is promoted by moderate cooling. The results show that optimal strength-toughness combination of the Ti551 alloy is achieved under the composite heat treatment of 900 ℃×2 h+ air cooling, then followed by 550 ℃×6 h aging, which is closely associated with the regulatory role of cooling rate. Acicular secondary α phase can be induced in the transformed β microstructure by higher cooling rate, and the alloy’s strength-plasticity matching effect is further enhanced by the subsequent aging treatment.
-
Key words:
- Ti551 titanium alloy /
- heat treatment /
- micro-structure /
- mechanical properties
-
图 3 拉伸和冲击试验试样示意（单位：mm）
（a）拉伸试验; （b）冲击试验
Figure 3. Schematic diagram of tensile test specimen and impact test specimen
图 4 不同热处理温度下Ti551合金的显微组织
光学显微组织（500×）：(a)1#, (b)2#，(c)3#，(d)4#，(e)5#，(f)6#, (g)7#;SEM形貌（5000×）：(h)1#, (i)2#，(j)3#，(k)4#，(l)5#，(m)6#, (n)7#
Figure 4. Microstructure of Ti551 alloy after solid solution at different heat treatment temperatures
图 5 不同热处理工艺下试样的室温拉伸应力应变曲线
Figure 5. Stress-strain curves of tensile tests for specimens after solid solution under different heat treatment processes
图 6 不同热处理工艺条件下Ti551合金力学性能对比
(a)～(c)抗拉和屈服强度对比; (d)～(f)伸长率对比; (g)～(i)冲击功对比
Figure 6. Comparison of mechanical properties of Ti551 alloy after solid solution under different heat treatment process conditions
图 7 Ti551合金经不同热处理工艺后试样强韧性对比
Figure 7. Strength-toughness comparison of Ti551 alloy specimens after solid solution under different heat treatment process conditions
表 1 Ti551钛合金化学成分
Table 1. Chemical compositions of Ti551 alloy
% Position Al Sn Zr Mo V Cr Fe Si O Top 5.23 0.99 0.98 1.46 1.03 0.92 0.13 0.017 0.082 Middle 5.28 0.99 0.97 1.47 1.03 0.94 0.13 0.016 Bottom 5.28 0.99 1.01 1.45 1.05 0.99 0.15 0.015 0.080 Standard 4.0～6.0 0.5～2.0 0.5～2.0 0.5～2.0 0.5～2.0 0.5～2.0 ≤0.2 ≤0.1 ≤0.2 
下载: 导出CSV
表 2 热处理工艺试验参数
Table 2. Heat treatment process parameters
Specimen
numberSpecimen
specification/mmSolid solution Aging Heat treatment temperature/℃ Time/h Cooling method Heat treatment temperature/℃ Time/h Cooling method 1# Ø13×80 900 2 AC 550 6 AC 2# Ø13×80 900 2 AC 600 6 AC 3# Ø13×80 900 2 AC 650 6 AC 4# Ø13×80 930 2 AC 550 6 AC 5# Ø13×80 950 2 AC 550 6 AC 6# Ø13×80 900 2 FC 550 6 AC 7# R465×35 900 2 AC 550 6 AC
下载: 导出CSV
-
[1] YAN S, SONG G L, LI Z, et al. A state-of-the-art review on passivation and biofouling of Ti and its alloys in marine environments[J]. Journal of Materials Science & Technology, 2018, 34(3): 421-435. doi: 10.1016/j.jmst.2017.11.021 [2] YIN Y C, SUN Z J, XUE D, et al. Effect of post heat treatment on the microstructure and properties of as-annealed TC4 ELI alloy[J]. Iron Steel Vanadium Titanium, 2024, 45(3): 55-64. (尹艳超, 孙志杰, 薛达, 等. 后处理对退火态TC4 ELI合金显微组织与性能的影响[J]. 钢铁钒钛, 2024, 45(3): 55-64.YIN Y C, SUN Z J, XUE D, et al. Effect of post heat treatment on the microstructure and properties of as-annealed TC4 ELI alloy[J]. Iron Steel Vanadium Titanium, 2024, 45（3）: 55-64. [3] LI J L, SHEN M H, MA R F, et al. Marine resource economy and strategy under the background of marine ecological civilization construction[J]. Journal of Natural Resources, 2022, 37(4): 829-849. (李加林, 沈满洪, 马仁锋, 等. 海洋生态文明建设背景下的海洋资源经济与海洋战略[J]. 自然资源学报, 2022, 37(4): 829-849. doi: 10.31497/zrzyxb.20220401LI J L, SHEN M H, MA R F, et al. Marine resource economy and strategy under the background of marine ecological civilization construction[J]. Journal of Natural Resources, 2022, 37（4）: 829-849. doi: 10.31497/zrzyxb.20220401 [4] LUO H, DENG H, YUAN W, et al. Effect of heat treatment holding time on microstructure and tensile properties of Ti55511 alloy[J]. Rare Metal Materials and Engineering, 2025, 54(5): 1185-1193. [5] LUO H J, DENG H, YUAN W H, et al. Effect of heat treatment holding time on microstructure and tensile properties of Ti55511 alloy[J]. Rare Metal Materials and Engineering, 2025, 54(5): 1185-1193. (罗恒军, 邓浩, 袁武华, 等. 热处理保温时间对Ti55511钛合金显微组织和拉伸性能的影响[J]. 稀有金属材料与工程, 2025, 54(5): 1185-1193). doi: 10.12442/j.issn.1002-185X.20240192LUO H J, DENG H, YUAN W H, et al. Effect of heat treatment holding time on microstructure and tensile properties of Ti55511 alloy[J]. Rare Metal Materials and Engineering, 2025, 54（5）: 1185-1193. doi: 10.12442/j.issn.1002-185X.20240192 [6] YANG L, YU H, WANG Z R, et al. Effect of heat treatment process on microstructure and mechanical properties of Ti-555 armored titanium alloy[J]. Transactions of Materials and Heat Treatment, 2024, 45(11): 93-100. (杨柳, 于辉, 王占瑞, 等. 热处理工艺对Ti-555装甲钛合金微观组织与力学性能的影响[J]. 材料热处理学报, 2024, 45(11): 93-100. doi: 10.13289/j.issn.1009-6264.2024-0336YANG L, YU H, WANG Z R, et al. Effect of heat treatment process on microstructure and mechanical properties of Ti-555 armored titanium alloy[J]. Transactions of Materials and Heat Treatment, 2024, 45（11）: 93-100. doi: 10.13289/j.issn.1009-6264.2024-0336 [7] YUAN F, CAO Y, HE W J, et al. Effect of heat treatment process on mechanical properties and wear resistance of TA15 titanium alloy[J]. Transactions of Materials and Heat Treatment, 2025, 46(1): 30-40. (袁飞, 曹宇, 何维均, 等. 热处理工艺对TA15钛合金力学性能和耐磨性的影响[J]. 材料热处理学报, 2025, 46(1): 30-40. doi: 10.13289/j.issn.1009-6264.2024-0111YUAN F, CAO Y, HE W J, et al. Effect of heat treatment process on mechanical properties and wear resistance of TA15 titanium alloy[J]. Transactions of Materials and Heat Treatment, 2025, 46（1）: 30-40. doi: 10.13289/j.issn.1009-6264.2024-0111 [8] WEI N, ZHANG C H, YAN Z, et al. Effect of different heat treatment processes on the microstructure and properties of TC6 titanium large-sized bars[J]. World Nonferrous Metals, 2025(6): 5-7. (卫娜, 张晨辉, 闫钊, 等. 不同热处理工艺对TC6大规格棒材组织和性能的影响[J]. 世界有色金属, 2025(6): 5-7. doi: 10.3969/j.issn.1002-5065.2025.06.002WEI N, ZHANG C H, YAN Z, et al. Effect of different heat treatment processes on the microstructure and properties of TC6 titanium large-sized bars[J]. World Nonferrous Metals, 2025（6）: 5-7. doi: 10.3969/j.issn.1002-5065.2025.06.002 [9] GAO X, ZENG W, WANG Y, et al. Evolution of equiaxed alpha phase during heat treatment in a near alpha titanium alloy[J]. Journal of Alloys and Compounds, 2017, 725: 536-543. doi: 10.1016/j.jallcom.2017.07.195 [10] XUE X, SHI D, ZHAO L. Experimental study on residual stress and deformation control during machining of TC18 titanium alloy long axis[J]. Materials, 2025, 18(12): 2788. doi: 10.3390/ma18122788 [11] WANG K, LI M Q. Effects of heat treatment and hot deformation on the secondary α phase evolution of TC8 titanium alloy[J]. Materials Science and Engineering: A, 2014, 613: 209-216. doi: 10.1016/j.msea.2014.06.056 [12] YU R, CHEN Q, WANG P, et al. Effects of solution temperature and aging time on the microstructure and mechanical properties of TG6 titanium alloy[J]. Journal of Materials Engineering and Performance, 2022, 31(2): 1456-1464. doi: 10.1007/s11665-021-06285-z [13] PENG H, YE W, LIU J, et al. Probabilistic distribution model of grain boundary α phase length in titanium alloys[J]. Journal of Materials Research and Technology, 2025, 36: 8860-8864. doi: 10.1016/j.jmrt.2025.05.087 [14] FAN Y T, PENG L, LI J M, et al. Microstructure and mechanical properties of TA16 bar with different heat treatment temperatures[J]. Iron Steel Vanadium Titanium, 2025, 46(3): 53-59. (范玉婷, 彭力, 李京懋, 等. 不同热处理温度对TA16棒材显微组织和力学性能的影响[J]. 钢铁钒钛, 2025, 46(3): 53-59.FAN Y T, PENG L, LI J M, et al. Microstructure and mechanical properties of TA16 bar with different heat treatment temperatures[J]. Iron Steel Vanadium Titanium, 2025, 46(3): 53-59. [15] ZHANG X F, CHEN M, LIU X Y, et al. Effect of heat treatment on microstructure and properties of Ti84Al11FeMo4 titanium alloy[J]. Iron Steel Vanadium Titanium, 2022, 43(6): 66-70,77. (张雪峰, 陈敏, 刘许旸, 等. 热处理对钛合金Ti84Al11FeMo4组织和性能的影响[J]. 钢铁钒钛, 2022, 43(6): 66-70,77. doi: 10.7513/j.issn.1004-7638.2022.06.010ZHANG X F, CHEN M, LIU X Y, et al. Effect of heat treatment on microstructure and properties of Ti84Al11FeMo4 titanium alloy[J]. Iron Steel Vanadium Titanium, 2022, 43（6）: 66-70,77. doi: 10.7513/j.issn.1004-7638.2022.06.010 -
图(7) / 表(2)
计量
- 文章访问数: 2
- HTML全文浏览量: 0
- PDF下载量: 2
- 被引次数: 0
