正火温度对电弧增材制造Ti-6Al-4V组织与性能的影响

徐国建; 柳晋; 陈冬卅; 马瑞鑫; 苏允海

doi:10.12073/j.hjxb.20191022002

正火温度对电弧增材制造Ti-6Al-4V组织与性能的影响

沈阳工业大学，沈阳，110870

基金项目: 国家重点研发计划(2017YFB1103600)

详细信息

作者简介:
徐国建，1959年出生，博士，教授，博士研究生导师；主要从事增材制造及激光焊接技术等方面的研究；发表论文50余篇；Email：xuguojian1959@qq.com

中图分类号: TG 422.3
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出版历程
- 收稿日期: 2019-10-21
- 网络出版日期: 2020-07-12
- 刊出日期: 2019-12-31

Effect of normalizing temperature on microstructure and properties of Ti-6Al-4V fabricated by arc additive manufacturing

Shenyang University of Technology, Shenyang, 110870, China

摘要

摘要: 利用TIG电弧增材制造技术制备了TC4钛合金样件，并对样件进行了正火处理. 结果表明，经正火处理后的试样组织由α相和β相组成；在750 ~ 950 ℃范围内，随着正火温度的升高，针状初生α相变短变粗，并逐渐向网篮组织方向转变；在950 ~ 1 050 ℃温度范围内，随着温度的升高，部分初生α相聚合长大，并向着“伪等轴晶”方向转化，在1 050 ℃形成了“伪等轴晶”初生α相 + 细小针状初生α相 + 细小针状初生α相之间的α + β组织，针状初生α相随着温度的升高变短变细. 最佳条件(850 ℃/2 h/空冷)下y方向的抗拉强度900.4 MPa、屈服强度820.4 MPa、断后伸长率9.3%、断面收缩率27.4%，z方向的抗拉强度890.1 MPa、屈服强度790.1 MPa、断后伸长率10.8%、断面收缩率31.0%，其性能接近锻件标准要求；沉积态与正火处理态的硬度值变化不大；拉伸试样(y和z方向)断口形貌均布满韧窝，属于塑性断裂.
- TC4(Ti-6Al-4V) /
- 正火处理 /
- TIG电弧增材制造 /
- 显微组织 /
- 力学性能
Abstract: The samples of TC4 titanium alloy were prepared by TIG arc additive manufacturing, and the samples were normalized. The results show that the microstructure of the sample is composed of α phase and β phase after normalizing treatment. And the acicular primary α phase becomes shorter and thicker with the increase of normalizing temperature at the range of 750 ~ 950 °C, and gradually changes to the direction of net basket structure. At the range of 950 ~ 1 050 °C, some primary α phases develop toward "pseudo-equiaxed crystals", and form structures which comprises the "pseudo-equiaxed crystals" primary α phase + the fine needle-like primary α phase + (α + β) structures between the fine needle-like primary α phases at 1 050 °C. The better mechanical properties of the present work (in conditions of 850 °C/2 h/AC) show that tensile strength, yield strength, elongation and reduction of the area in y direction are 900.4, 820.4 MPa, 9.3%, and 27.4% respectively, and tensile strength, yield strength, elongation and reduction of the area in z direction are 890.1, 790.1 MPa, 10.8%, and 31.0% respectively, which is close to the standard requirements for forgings. The hardness of sedimentary state and normalizing state has little changes. The fracture morphology of tensile specimen (z tensile specimen and y tensile specimen) is full of dimples and belongs to plastic fracture.
- TC4 (Ti-6Al-4V) /
- normalizing treatment /
- TIG arc additive manufacturing (TIG AAM) /
- microstructure /
- mechanical properties

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图 1 构件宏观形貌

Figure 1. Macrostructure morphologies of component

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图 2 钛合金沉积构件取样位置示意图

Figure 2. Sampling positions for additive manufactured titanium alloy component

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图 3 拉伸尺寸示意图(mm)

Figure 3. Schematic of tensile specimen size

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图 4 不同状态下试样显微组织

Figure 4. Microstructure of specimen in different states. (a) as-deposited; (b) 750 ℃/2 h/ AC; (c) 850 ℃/2 h/ AC; (d) 950 ℃/2 h/ AC; (e) 1 050 ℃/2 h/ AC; (f) SEM morphology of the rectangle area

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图 5 X射线衍射分析结果

Figure 5. Analysis results of X-ray diffraction

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图 6 不同正火温度下样件的力学性能

Figure 6. Mechanical properties of the selected sample in different normalizing temperature. (a) y direction; (b) z direction

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图 7 沉积态及不同正火温度下的硬度分布值

Figure 7. Hardness distribution in deposited state and in different normalizing temperatures

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图 8 沉积态与正火态的拉伸试样断口形貌

Figure 8. Fracture morphology of sample in as-deposited and in normalized state. (a) y in deposited; (b) y in normalizing; (c) z in deposited; (d) z in normalizing

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表 1 Ti-6Al-4V的化学成分(质量分数，%)

Table 1 Chemical compositions of Ti-6Al-4V

材料	Al	V	C	Fe	H	O	N	Ti
焊丝	6.08	4.15	0.012	0.04	0.097	0.088	0.062	余量
基板	6.10	4.0	0.08	0.03	0.015	0.2	0.03	余量

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表 2 焊接工艺参数

Table 2 Processing parameters of additive manufacturing

焊接电流 I/A	扫描速度 v₁/(mm·s⁻¹)	送丝速度 v₂/(m·min⁻¹)	焊丝与工件表面距离 L/mm	焊丝与焊枪角度 α/(°)	气体流量 q/(L·min⁻¹)	搭接率 δ(%)	基板尺寸 mm × mm × mm
160	8	1.4	3	40	10	40	100 × 100 × 20

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表 3 电弧增材制造钛合金样件的热处理工艺参数

Table 3 Heat treatment parameter of titanium alloy fabricated by arc additive manufacturing

样品	加热温度 T/℃	加热速度 v₃/(℃·min⁻¹)	加热时间 t/h	冷却方式
0	0	0	0	无
1	750	6	2	空冷
2	850	6	2	空冷
3	950	6	2	空冷
4	1 050	6	2	空冷

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参考文献(12)

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