Ti6Al4V合金整体零件的两步热等静压近净成形工艺探究

摘要/Abstract

摘要：

针对热等静压整体成形高温合金零件容易产生部分区域致密度较低、整体性能不均一的问题,提出了热等静压两步成形方法,在较低的温度和压力作用下成形为不带连通孔隙的原始零件,去除控形模具后用合适的温度压力作用使不致密区域致密,提高零件均一性。以Ti6Al4V粉末材料为例,使用有限元模拟和实验测试相结合的方法,确定了两步成形法的工艺参数,并成形了叶盘零件。SEM结果显示：热等静压两步法成形的零件组织由板条状α+β相组成,原始颗粒边界消失,不连通孔隙闭合。断口形貌显示:在合适的两步成形工艺参数加载下,粉末颗粒冶金结合牢固,
不再成为裂纹起始处,拉伸强度提高。两步法拉伸性能略优于常规热等静压拉伸性能,性能达到同规模锻件水平。

关键词: 热等静压两步成形, Ti6Al4V, 有限元模拟, 力学性能

Abstract:

Monolithic superalloy parts shaped by hot isostatic pressing may exist low density region which will cause uneven overall performance.This paper proposed a two-step hot isostatic pressing method:at low temperature and pressure original parts were shaped without connected pores from alloy powder,then the low density regions were densed at an appropriate temperature and pressure after removing capsule and shape-control mold,which could guarantee uniform performance. Taking Ti6Al4V powder material as an example,two-step HIP parameters were determined by combining finite element simulation and experimental tests,with which bladed disk parts were made.The SEM results show that:it is fine and homogeneous strip α+β phase in the parts and there is no prior particle boundary or connected pores, which contribute to the good performance of parts.The fracture morphology analysis shows that: the powder particles are metallurgically bonded firmly and no longer the crack source given appropriate processing parameters.Tensile strength of two-step HIP parts is slightly better than that of conventional HIP and as same as the forging's.

Key words: two-step hot isosatic pressing(HIP), Ti6Al4V, finite element simulation, mechanics property

中图分类号:

TF124

黄俊, 薛鹏举, 魏青松, 史玉升. Ti6Al4V合金整体零件的两步热等静压近净成形工艺探究[J]. 中国机械工程, 2015, 26(18): 2539-2544.

Huang Jun, Xue Pengju, Wei Qingson, Shi Yusheng. Research on Near-Net-Shaping Ti6Al4V Alloy Parts under Two-Step Hot Isostatic Pressing[J]. China Mechanical Engineering, 2015, 26(18): 2539-2544.

参考文献

[1]张义文.热等静压技术新进展[J].粉末冶金工业,2009(4):32-40.
Zhang Yiwen.Research and Development in P/M Superalloy[J].Powder Metallurgy Industry,2009(4):32-40.
[2]Bocanegra-bernal M H. Hot Isostatic Pressing (HIP) Technology and Its Applications to Metals and Ceramics[J]. Journal of Materials Science,2004,39(21):6399-6420.
[3]Leyens C,Peters M.Titanium and Titanium Alloys[M].Weinheim:Wiley-VCH,2005.
[4]赵永庆.高温钛合金研究[J].钛工业进展,2001,1（1）：33-39.
Zhao Yongqing.Research on High Temperature Titanium Alloys[J].Titanium Industry Progress,2001,1(1):33-39.
[5]张晓伟.Ti6Al4V合金表面激光熔覆功能复合涂层研究进展[J].稀有金属材料与工程,2012,41(1):178-183.
Zhang Xiaowei.Research Progress of Functional Composite Coatings on Ti6Al4V Alloy Surface Prepared by Laser Cladding Technique[J].Rare Metal Materials and Engineering,2012,41(1):178-183.
[6]刘国承,史玉升,魏青松,等.316L粉末热等静压致密化过程数值模拟[J].华中科技大学学报(自然科学版),2011,39(10):23-27.
Liu Guocheng,Shi Yusheng,Wei Qingsong,et al.Numerical Simulation of the Densification of 316L Powder during Hot Isostatic Pressing[J].Journal of Huazhong University of Science and Technology(Natural Science Edition),2011,39(10):23-27.
[7]Zhang K,Mei J,Wain N,et al.Effect of Hot-isostatic- pressing Parameters on the Microstructure and Properties of Powder Ti-6Al-4V Hot-isostatically-pressed Samples[J].Metallurgical and Materials Transactions A,2010(4):1033-1045.
[8]崔忠圻,覃耀春.金属与热处理[M].2版.北京：机械工业出版社,2007.
[9]Das S,Wohlert M,Beaman J J,et al.Processing of Titanium Net Shapes by SLS/HIP[J].Materials and Design,1999,20:115-121.
[10]Yuan W X,Mei J,Samarov V,et al.Computer Modelling and Tooling Design for Near Net Shaped Components Using Hot Isostatic Pressing[J].Journal of Materials Processing Technology,2007,182(1/3):39-49.
[11]Shima S,Oyane M.Plasticity Theory for Porous Metals[J].International Journal of Mechanical Sciences,1976,18(6):285-291.
[12]Sanchez L,Ouedraogo E,Federzoni L,et al.New Viscoplastic Model to Simulate Hot Isostatic Pressing[J].Powder Metallurgy, 2002,45(4):329-334.
[13]Hua L,Qin X,Mao H,et al.Plastic Deformation and Yield Criterion for Compressible Sintered Powder Materials[J].Journal of Materials Processing Technology,2006,180(1):174-178.
[14]陆恒,魏青松,薛鹏举,等.Inconel 625粉末盘热等静压近净成形过程模拟与验证[J].中国机械工程,2013,24(19):2675-2680.
Lu Heng,Wei Qingsong,Xue Pengjun,et al.Numerical Simulation and Verification of Near-net-shaping Inconel625 Powder Disk under Hot Isostatic Pressing[J].China Mechanical Engineering,2013,24(19):2675-2680.
[15]王学滨.基于实测剪切应力及局部应变的Ti-6Al-4V绝热剪切带的峰值温度估算[J].材料与工程,2013,42(2):320-324.
Wang Xuebing.An Assessment of the Peak Temperature in the Adiabatic Shear Band of Ti-6Al-4V Based on the Measured Shear Stress and Local Strain[J].Rare Metal Materials and Engineering,2013,42(2):320-324.
[16]Stefansson N,Semiatin S L.Mechanisms of Globularization of Ti-6Al-4V during Static Heat Treatment.Mater. Trans. A,2002,34:691-698.