摘要
针对截面厚度达200 mm的损伤容限型Ti-6Al-4V ELI合金锻件,开展了β热处理工艺和准β热处理工艺试验,对比分析了热处理工艺对锻件强度、塑性、断裂韧度、疲劳裂纹扩展速率的影响。研究结果表明,随着第一重退火温度从Tβ+15℃升高到Tβ+30℃、Tβ+60℃,锻件塑性下降明显。经准β工艺热处理后,锻件的β晶粒尺寸较小,塑性明显优于β热处理工艺。强度、断裂韧度和疲劳裂纹扩展速率对β热处理温度不敏感。为达到良好的强度-塑性-韧性的综合性能匹配,Ti-6Al-4V ELI合金厚截面锻件宜采用较低热处理温度(如Tβ+15℃)的β热处理工艺或准β热处理工艺。
The influence of β heat treatment and quasi-β heat treatment on strength,plasticity,fracture toughness and fatigue crack propagation rate of damage-tolerant titanium alloy Ti-6 Al-4 V ELI thick section forgings have been studied. The results show that,the increasing of the first annealing temperature from Tβ+ 15 ℃ to Tβ+ 30 ℃,Tβ+ 60 ℃will lead to lower plasticity observably. The plasticity of quasi-β heat treatment process is obviously superior to β heat treatment process due to its smaller β grain size. Strength,fracture toughness and fatigue crack propagation rate are not sensitive to the temperature of heat treatment. In order to achieve a good strength-plasticity-toughness comprehensive performance match,Ti-6 Al-4 V ELI thick section forgings should adopt β heat treatment process with lower annealing temperature or quasi-β heat treatment process.
引文
[1]颜鸣皋,吴学仁,朱知寿.航空材料技术的发展现状与展望[J].航空制造技术,2003(12):19-25.
[2]朱知寿.航空结构用新型高性能钛合金材料技术研究与发展[J].航空科学技术,2012(1):5-9.
[3]朱知寿,王新南,童路,等.航空用损伤容限型钛合金研究与应用[J].中国材料进展,2010,29(5):14-17.
[4]王文杰.准β热处理工艺对TC4-DT钛合金组织和性能的影响[J].钛工业进展,2016,33(1):23-27.
[5]朱知寿,马少俊,王新南,等. TC4-DT损伤容限型钛合金疲劳裂纹扩展特性的研究[J].钛工业进展,2005,22(6):10-13.
[6]王新南,童路,朱知寿,等.中强高损伤容限型TC4-DT钛合金热处理冷却速率与强韧性的关系研究[J].稀有金属材料与工程,2008,37(增刊3):537-540.
[7]祝力伟,王新南,朱知寿.不同热处理工艺下TC4-DT钛合金的显微组织及力学性能[J].钛工业进展,2012,29(1):9-12.
[8]朱知寿,王庆如,王新南,等.一种钛合金准β热处理工艺:200410090864. 3[P]. 2008-07-30.
[9]Sinha V,Soboyejo W O. An investigation of the effects of colony macrostructure on fatigue crack growth in Ti-6Al-4V[J]. Materials Science and Engineering A,2001,319-321:607-612.
[10]Cao C X. Change of material selection criterion and development of high damage-tolerant titanium alloy[J]. Acta Metallurgica Sinica,2002,38(Suppl 1):4-11.
[11]Lütjering G. Influence of processing on microstructure and mechanical properties of(α+β)titanium alloys[J]. Materials Science and Engineering A,1998,243(1/2):32-45.
[12]Leyens C,Peters M. Titanium and Titanium Alloys[M].Weinheim:Wiley-VCH,2005:28-31.