The Effect of Heat Treatments on Microstructure and Mechanical Properties of As-Extruded Ti-6Al-4V Alloy Rod from Blended Elemental Powders

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In this study, Ti-6Al-4V bars were first prepared by extrusion of powder compacts from blended powder mixtures in the beta phase region, then the as-extruded bars were heat-treated following four different conditions: beta quenching and aging (βQA), broken up structure (BUS) treatment, solution treatment and aging (STA) and recrystallization annealing (RA). The effect of the heat treatments on microstructure and mechanical properties was studied using optical microscopy, scanning electron microscopy, and mechanical test to determine which heat-treatment condition has the greatest impact on the mechanical properties of the as-extruded Ti-6Al-4V alloy. The results show that the as-extruded condition has the best balance of strength (1120 MPa of UTS) and ductility (11% of elongation to failure). βQA and STA lead to a slight increase in strength but ductility decreases considerably. After BUS and RA treatments, both strength and ductility are reduced. The relationship between processing, microstructure and properties was studied, and their implications towards fatigue behaviour and fracture toughness were discussed.

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Edited by:

Huiping Tang, Ma Qian, Yong Liu, Peng Cao and Gang Chen

Pages:

45-51

Citation:

C. Romero et al., "The Effect of Heat Treatments on Microstructure and Mechanical Properties of As-Extruded Ti-6Al-4V Alloy Rod from Blended Elemental Powders", Key Engineering Materials, Vol. 770, pp. 45-51, 2018

Online since:

May 2018

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$38.00

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[1] Lee, Y.T., M. Peters, and G. Wirth, Effects of thermomechanical treatment on microstructure and mechanical properties of blended elemental Ti-6Al-4V compacts. Materials Science and Engineering: A, 1988. 102(1): pp.105-114.

DOI: https://doi.org/10.1016/0025-5416(88)90538-1

[2] Wang, H., Z.Z. Fang, and P. Sun, A critical review of mechanical properties of powder metallurgy titanium. International Journal of Powder Metallurgy, 2010. 46(5): pp.45-57.

[3] Lou, J., et al., Effects of LaB6 additions on the microstructure and mechanical properties of a sintered and hot worked P/M Ti alloy. Journal of Alloys and Compounds, 2016. 674: pp.116-124.

DOI: https://doi.org/10.1016/j.jallcom.2016.02.163

[4] Cao, Y., et al., Characterization of fatigue properties of powder metallurgy titanium alloy. Materials Science and Engineering: A, 2016. 654: pp.418-425.

[5] Yang, F., et al., Microstructural evolution during extrusion of a Ti/Al/Al35V65 (Ti–6Al–4V) powder compact and the mechanical properties of the extruded rod. Materials Science and Engineering: A, 2014. 598: pp.360-367.

DOI: https://doi.org/10.1016/j.msea.2014.01.055

[6] Liang, C., et al., Microstructures and tensile mechanical properties of Ti–6Al–4V bar/disk fabricated by powder compact extrusion/forging. Materials Science and Engineering: A, 2014. 619: pp.290-299.

DOI: https://doi.org/10.1016/j.msea.2014.09.083

[7] Eylon, D., R. Vogt, and F. Froes, Property Improvement of Low Chlorine Titanium Alloy Blended Elemental Powder Compacts by Microstructure Modification. Progress in Powder Metallurgy 1986., 1986. 42: pp.625-634.

[8] Eylon, D. and F.H. Froes, Tensile and fatigue strength improvement of titanium PM alloys through microstructural refinement, in Strength of Metals and Alloys (ICSMA 8). 1989, Pergamon: Oxford. pp.527-533.

DOI: https://doi.org/10.1016/b978-0-08-034804-9.50080-2

[9] Hagiwara, M., et al., Fatigue property enhancement of α-β titanium alloys by blended elemental P/M approach. ISIJ International, 1991. 31(8): pp.922-930.

DOI: https://doi.org/10.2355/isijinternational.31.922

[10] ASTM, Standard Specification for Titanium and Titanium Alloy Bars and Billets, in ASTM B348-13. 2013, ASTM International.

[11] Lütjering, G., Influence of processing on microstructure and mechanical properties of (α+β) titanium alloys. Materials Science and Engineering: A, 1998. 243(1–2): pp.32-45.

DOI: https://doi.org/10.1016/s0921-5093(97)00778-8

[12] Kar, S., et al., Modeling the tensile properties in β-processed α/β Ti alloys. Metallurgical and Materials Transactions A, 2006. 37(3): pp.559-566.