Effect of Argon-Induced Porosity on Mechanical Properties of Powder Metallurgy Titanium Alloy Components using Hot Isostatic Pressing

doi:10.1007/s40195-021-01243-z

Abstract

Abstract:

This work reported the Ar-induced porosity in powder metallurgy Ti-5Al-2.5Sn alloy prepared by hot isostatic pressing (HIPing). The obtained microstructures of powder compacts were studied through optical and scanning electron microscopes, X-ray tomography, and the mechanical properties evaluated through tensile and impact tests. The results showed that the Ar-induced porosity is related to the hollow powder with gas bubble and the Ar leakage of sealed container during the powder densification. The hollow powder with gas bubble shows no obvious effects on mechanical properties of as-HIPed powder compacts. The Ar content decreases with the increasing shrinkage of encapsulated powder. 0.7% Ar-induced porosity degrades the impact toughness, but no reductions of tensile properties were obtained. Ar content test is an effective method to detect the powder compacts with Ar concentration.

Key words: Titanium alloys, Hot isostatic pressing, Argon concentration, Porosity

Min Cheng, Jie Wu, Zheng-Guan Lu, Rui-Peng Guo, Lei Xu, Rui Yang. Effect of Argon-Induced Porosity on Mechanical Properties of Powder Metallurgy Titanium Alloy Components using Hot Isostatic Pressing[J]. Acta Metallurgica Sinica (English Letters), 2021, 34(10): 1386-1394.

Figures/Tables 11

Fig. 1 HIPing route and densification curve of Ti-5Al-2.5Sn powders. The red squares indicate the interrupted HIPing conditions

Table 1 Chemical compositions of Ti-5Al-2.5Sn powders (wt%)

Al	Sn	Fe	C	O	N	H	Ar	Ti
4.97	2.5	0.03	0.007	0.078	0.018	0.002	< 0.0001	Bal

Fig. 2 Characterization of Ti-5Al-2.5Sn powders: a particle size distribution, b powder morphology, c cross-sectional OM image

Fig. 3 OM images showing the cross-sectional micrographs of partially HIPed powder compacts interrupted at: a 690 °C, b 740 °C, c 890 °C, d 940 °C/0.5 h

Table 2 Ar content, relative density and nondestructive inspections testing results of Ti-5Al-2.5Sn powder compacts

Samples	Relative density (%)	Ar content (ppm)	RI	PI
S1	99.9	< 1	+	+
S2	99.7	10	+	+
S3	99.4	40	+	+
S4	99.3	260	+	+

Fig. 4 Microstructures of sample S1: a OM, b SEM-BSE image. BSE stands for backscattering electrons

Fig. 5 Cross-sectional micrographs of sample S4 at: a low, b high magnifications

Fig. 6 a, b Micro-CT reconstruction images, c pore size distribution histograms, d cumulative pore distributions of samples S1 and S4

Table 3 Mechanical properties of samples S1 and S4

Samples	UTS (MPa)	0.2%YS (MPa)	El. (%)	A (kJ/m²)
S1	801	692	14.0	620
S4	792	687	12.5	175

Fig. 7 SEM images of the fracture surfaces of tensile samples: a S1, b-d S4

Fig. 8 SEM images of the fracture surfaces of impact samples at the crack initiations: a S1, b S4. The red arrows indicate the pores and the red dots indicate the PPBs

References 33

[1]	J.C. Williams, E.A. Starke, Acta Mater. 51, 5775 (2003) DOI URL
[2]	D. Banerjee, J.C. Williams, Acta Mater. 61, 844 (2013) DOI URL
[3]	M. Cheng, B.B. Yu, R.P. Guo, X.H. Shi, L. Xu, J.W. Qiao, R. Yang, J. Mater. Res. Technol. 10, 153 (2021) DOI URL
[4]	L. Bolzonia, E.M. Ruiz-Navas, E. Gordo, Mater. Des. 110, 317 (2016) DOI URL
[5]	F. Yang, B. Gabbitas, J. Alloys Compd. 695, 1455 (2017) DOI URL
[6]	C. Qiu, D. Yang, G. Wang, Q. Liu, Mater. Sci. Eng. A 769, 138461 (2020)
[7]	J. Wu, R. Guo, L. Xu, Z.G. Lu, Y.Y. Cui, R. Yang, J. Mater. Sci. Technol. 33, 172 (2017)
[8]	L.T. Chang, W.R. Sun, Y.Y. Cui, R. Yang, Mater. Sci. Eng. A 682, 341 (2017)
[9]	Y. Kim, E.-P. Kim, Y.-B. Song, S.H. Lee, Y.S. Kwon, J. Alloys Compd. 603, 207 (2014) DOI URL
[10]	Z.G. Lu, J. Wu, R.P. Guo, L. Xu, R. Yang, Acta Metall. Sin. -Engl. Lett. 30, 621 (2017)
[11]	C. Cai, B. Song, P. Xue, Q. Wei, C. Yan, Y. Shi, Mater. Des. 106, 371 (2016) DOI URL
[12]	R. Guo, L. Xu, Z. Chen, Q. Wang, B.Y. Zong, R. Yang, Mater. Sci. Eng. A 706, 57 (2017)
[13]	R.P. Guo, L. Xu, B. Zong, R. Yang, Mater. Des. 99, 341 (2016) DOI URL
[14]	W.X. Yuan, J. Mei, V. Samarov, D. Seliverstov, X. Wu, J. Mater. Process. Technol. 182, 39 (2007) DOI URL
[15]	R. Guo, L. Xu, B.Y. Zong, R. Yang, Acta Metall. Sin. -Engl. Lett. 30, 735 (2017)
[16]	R. Guo, L. Xu, J. Wu, R. Yang, B.Y. Zong, Mater. Sci. Eng. A 639, 327 (2015)
[17]	C. Van Nguyen, A. Bezold, C. Broeckmann, J. Mater. Process. Technol. 226, 134 (2015) DOI URL
[18]	D. Eylon, S.W. Schwenker, F.H. Froes, Metall. Trans. A 16, 1526 (1985)
[19]	R.P. Guo, L. Xu, C.G. Bai, J. Wu, Q.J. Wang, R. Yang, Chin. J. Nonferrous Met. 24, 2050 (2014)
[20]	L. Xu, R. Guo, C. Bai, J. Lei, R. Yang, J. Mater. Sci. Technol. 30, 1289 (2014) DOI
[21]	Y.T. Lee, H. Schurmann, K.J. Grundhoff, M. Peters, Powder Metall. Int. 22, 11 (1990)
[22]	Z. Lu, J. Wu, L. Xu, R. Yang, Acta Metall. Sin. -Engl. Lett. 32, 1329 (2019)
[23]	G. Lutjering, J.C. Williams, Titanium, 2nd edn. (Springer, Verlag, Berlin Heidelberg, 2007), p. 91
[24]	G. Chen, S.Y. Zhao, P. Tan, J. Wang, C.S. Xiang, H.P. Tang, Powder Technol. 333, 38 (2018) DOI URL
[25]	R. Gerling, R. Leitgeb, F.P. Schimansky, Mater. Sci. Eng. A 252, 239 (1998)
[26]	M.N. Ahsan, A.J. Pinkerton, R.J. Moatb, J. Shackleton, Mater. Sci. Eng. A 528, 7648 (2011)
[27]	D.P. Delo, H.R. Piehler, Acta Mater. 47, 2841 (1999) DOI URL
[28]	R.P. Guo, L. Xu, W.X. Cheng, J.F. Lei, R. Yang, Acta Metall. Sin. 52, 842 (2016)
[29]	R.P. Guo, L. Xu, J.F. Lei, R. Yang, Appl. Mech. Mater. 552, 274 (2014) DOI URL
[30]	H. Wang, Z.Z. Fang, P. Sun, Int. J. Powder Metall. 46, 45 (2010)
[31]	P. Kumar, K.S. Ravi Chandran, F. Cao, M. Koopman, Z.Z. Fang, Metall. Mater. Trans. A 47, 2150 (2016)
[32]	N. Kurgan, R. Varol, Powder Technol. 201, 242 (2010) DOI URL
[33]	Y. Yan, G.L. Nash, P. Nash, Int. J. Fatigue 55, 81 (2013)