Influences of Hot-Isostatic-Pressing Temperature on the Microstructure, Tensile Properties and Tensile Fracture Mode of 2A12 Powder Compact

doi:10.1007/s40195-016-0482-2

Abstract

Abstract:

2A12 aluminum alloy powders were hot-isostatic-pressed (HIPed) at representative temperatures for investigating the variation in microstructure, tensile property and fracture mode of the powder compact. It was found that the microstructure of raw powders changed from a dendrite structure to an equiaxed structure from room temperature to 600 °C. The liquid phase produced by the eutectic reaction in the powder was gradually increased and finally formed a liquid pathway that ran through the entire powder from 490 to 600 °C. Prior particle boundaries were observed in the powder compacts HIPed at 490 and 520 °C. The liquid phase in the powder compacts was squeezed into the powder boundaries and the triple points of powder when HIPed at 580 °C. However, the liquid phase located at the triple points of the powder was forced out and moved toward a small powder particle by HIP pressure under an HIPing temperature of 600 °C, which led to a decrease in the mechanical properties and relative density. Better comprehensive properties were obtained at HIPing temperatures of 490 and 580 °C. The low ductility exhibited by the P/M aluminum alloy HIPed at different temperatures was believed to arise from a combination of the existence of oxide film on the powder particle surface and the distribution characteristics of the liquid phase. Finally, three typical types of de-cohesion were classified.

Key words: Powder metallurgy, Hot-isostatic-pressing, Microstructural evolution, Fracture mode, Aluminum alloy, Mechanical properties

Gang Wang,Li-Hui Lang,Wen-Jun Yu,Xi-Na Huang,Fei Li. Influences of Hot-Isostatic-Pressing Temperature on the Microstructure, Tensile Properties and Tensile Fracture Mode of 2A12 Powder Compact[J]. Acta Metallurgica Sinica (English Letters), 2016, 29(10): 963-974.

Figures/Tables 15

Fig. 1 DSC curve of the 2A12 alloy powder

Fig. 2 Technology curve of HIP

Fig. 3 Specimens after HIP

Fig. 4 Morphology a, size distribution b and cross-sectional microstructure c of the rapidly solidified powder, EDS spectra of the precipitates marked 1 and 2 in c, d

Fig. 5 XRD spectra of 2A12 powders

Fig. 6 Microstructures of 2A12 powders isothermally held for 15 min at different temperatures: a 490 °C; b 520 °C; c 580 °C; d 600 °C

Fig. 7 Effect of the temperature on liquid phase fraction of 2A12 aluminum alloy powders

Fig. 8 Original powders a and microstructural evolution of powder compacts HIPed at different temperatures: f 490 °C; g 520 °C; h 580 °C; i 600 °C. The microstructure of powder compacts prepared by interrupted HIPing experiments after temperature preservation/pressure holding for 15 min at different temperatures: b 490 °C; c 520 °C; d 580 °C; e 600 °C. EDS spectra k, l of the marked points in h

Fig. 9 Squeezing process of liquid phase and tensile fracture morphology of powder compact at HIPing temperature 600 °C

Fig. 10 Relative densities and mechanical properties of powder compacts

Fig. 11 SEM pictures of fracture profiles: a 490 °C; b 520 °C; c 580 °C; d 600 °C

Fig. 12 Three typical types of de-cohesion: a direct fracture along with interface between solid particles; b propagation of cracks through the liquid phase itself; c direct detachment from the interface between solid phase and liquid phase

References

[1]	M. Nakai, T. Eto, Mater. Sci. Eng. A 285, 62 (2000)
[2]	W.S. Miller, L. Zhuang, J. Bottema, A.J. Wittebrood, P. De Smet, A. Haszler, Mater. Sci. Eng. A 280, 37 (2000)
[3]	J. Capus, Met. Powder Rep. 70, 294(2015)
[4]	J. Capus, Met. Powder Rep. 68, 12(2013)
[5]	A. Heinz, A. Haszler, C. Keidel, Mater. Sci. Eng. A 280, 102 (2000)
[6]	G.B. Schaffer, T.B. Sercombe, R.N. Lumley, Mater. Chem. Phys. 67, 85(2001)
[7]	J.M. Martín, F. Castro, J. Mater. Process. Technol. 144, 814(2003)
[8]	K.H. Min, S.P. Kang, B. Lee, J. Lee, Y.D. Kim, J. Alloys Compd. 419, 290(2006)
[9]	R.M. German, Sintering with a Liquid Phase, 9th edn. (Springer, Boston, 2014), pp. 247-303
[10]	Z.Y. Liu, T.B. Sercombe, G.B. Schaffer, Metall. Mater. Trans. A 38, 1351 (2007)
[11]	C.D. Boland, R.L. Hexemer, I.W. Donaldson, D.P. Bishop, Mater. Sci. Eng. A 559, 902 (2013)
[12]	G.B. Schaffer, B.J. Hall, S.J. Bonner, S.H. Huo, T.B. Sercombe, Acta Mater. 54, 131(2006)
[13]	A. G?k?e, F. F?nd?k, A.O. Kurt, Mater. Charact. 62, 730(2011)
[14]	C. Padmavathi, A. Upadhyaya, Trans. Indian Inst. Met. 64, 345(2011)
[15]	T.B. Sercombe, Mater. Sci. Eng. A 341, 163 (2003)
[16]	C.L. Qiu, M.M. Attallah, X.H. Wu, P. Andrews, Mater. Sci. Eng. A 564, 176 (2013)
[17]	J.T. Mater. Sci. Eng. A 465, 136 (2007)
[18]	L. Ceschini, A. Morri, G. Sambogna, J. Mater. Process. Technol. 204, 231(2008)
[19]	G. Ran, J. Zhou, Q.G. Wang, J. Alloys Compd. 421, 80(2006)
[20]	M.A. Islam, Z.N. Farhat, Wear 271, 1594 (2011)
[21]	L. Chang, W. Sun, Y. Cui, R. Yang, Mater. Sci. Eng. A 599, 186 (2014)
[22]	Q. Wang, S.G. Li, H.J. Lv, G. Shi, S.Y. Huang, J.L. Shi, Titan. Ind. Prog. 5, 16(2010)
[23]	S. Yu, L.H. Lang, S. Yao, G. Wang, X.N. Huang, Y.Q. Xu, Chin. J. Nonferr. Metal. 10, 2745(2015)
[24]	P.B. Li, T.J. Chen, S.Q. Zhang, R.G. Guan, Metals 5, 547 (2015)
[25]	Y. Zhang, S.K. Li, S.D. Chen, Powder Metall. Ind. 6, 13(1998)
[26]	Y.N. Dai, Binary Alloy Phase Diagrams, 4th edn. (Science Press, Beijing, 2009), pp. 56-59
[27]	J. Mi, P.S. Grant, Acta Mater. 56, 1597(2008)
[28]	C.X. Gu, South China University of Technology, 2015 (in Chinese)
[29]	R.M. German, A. Lal, J. Liu, Acta Mater. 47, 4615(1999)
[30]	Y. Xue, Beihang University, 2011 (in Chinese)
[31]	A.K. Jha, Illinois Institute of Technology, 1983
[32]	L. Dudas, W.A. Dean, Int. J. Powder Metall. 5, 113(1969)
[33]	B.Y. Huang, C.G. Li, L.K. Shi, G.Z. Qiu, T.Y. Zuo, China Materials Engineering Canon, 3rd edn. (Chemical Industry Press, Beijing, 2005), pp. 64-69
[34]	G.C. Guo, Liquid-Sintering Powder Metallurgy Material, 2nd edn. (Chemical Industry Press, Beijing, 2003), pp. 23-29
[35]	A. Mohammadzadeh, M. Azadbeh, H. Danninger, Powder Metall. 58, 123(2015)
[36]	M. Azadbeh, H. Danninger, C. Gierl-Mayer, Powder Metall. 56, 342(2013)
[37]	Y. Liu, X. Luo, Z. Li, J. Mater. Process. Technol. 214, 165(2014)
[38]	G.B. Schaffer, Mater. Forum 28, 65 (2004)
[39]	J. Campbell, J. Mater. Sci. 51, 96(2016)
[40]	K. Kondoh, A. Kimura, R. Watanabe, Powder Metall. 44, 161(2001)
[41]	G.N. Grayson, G.B. Schaffer, J.R. Griffiths, Mater. Sci. Eng. A 454-455, 99(2007)
[42]	T. Pieczonka, T. Schubert, S. Baunack, B. Kieback, Mater. Sci. Eng. A 478, 251 (2008)
[43]	M. Balog, C. Poletti, F. Simancik, M. Walcher, W. Rajner, J. Alloys Compd. 509, 235(2011)