Deformation characteristics of age hardened Ti-6Al-4V

Solution Treatment and Aging of Thick Rings from Titanium Alloy TI6AL4V

“…The properties of heat R2 (specimens 5 -8 ) were somewhat higher that the properties of heat R1 (specimens 1 -4 ) at the same thickness. This may be explained by the somewhat higher content of oxygen in heat R2 (Table 1), which may promote precipitation of an a 2 -phase [1].Analyzing the data of Table 2 we can see that the heat treatment by variant HT-1 provides the best combination of properties. For this reason we used variant HT-1 for all the subsequent tests.…”

“…The process of production of rings in quenched and aged condition is more complex and requires optimization with respect to several parameters in order to provide the specified mechanical properties, especially in the case of large sections. For this reason, quite a number of works have been devoted to determining the optimum conditions for the production of rings starting with melting of the alloy and ending with the heat treatment of ready articles [1,2]. The final mechanical properties of titanium alloys are determined by the morphology of the products of the martensitic transformation and of the decomposition of a¢-martensite during aging.…”

Effect of Retained β Phase on Mechanical Properties of Cast Ti-6Al-4V Alloy

“…The dark region is made of α phase with a thickness of about 4 µm, whereas thin bright region is shown as the β phase. The transformation from the β phase (bcc) to α phase (hcp) can occur along orientation relationship of (110) β //(0002) α and [1][2][3][4][5][6][7][8][9][10][11] β // [11][12][13][14][15][16][17][18][19][20] α .…”

“…Through this heat treatment, the tensile strength of this alloy is increased by α martensite formed from β phase after solution treatment, and the ne α and β phases decomposed from α martensite by aging treatment. [3][4][5][6] Moreover, further improvement of strength and toughness is obtained by nano-sized precipitates of α 2 (Ti 3 Al) phase after over-aging treatments at 723 923 K for long aging time. However, the problem of this heat treatment for the α 2 phase is that it takes a relatively long aging time generally over 360000 s. 5,7) On the other hand, several studies have reported that strength and ductility are more improved by solution treatment and subsequent aging for a short time of about 70 s, resulting from a strain-induced martensite transformation of the retained β phase under deformation.…”

“…[3][4][5][6] Moreover, further improvement of strength and toughness is obtained by nano-sized precipitates of α 2 (Ti 3 Al) phase after over-aging treatments at 723 923 K for long aging time. However, the problem of this heat treatment for the α 2 phase is that it takes a relatively long aging time generally over 360000 s. 5,7) On the other hand, several studies have reported that strength and ductility are more improved by solution treatment and subsequent aging for a short time of about 70 s, resulting from a strain-induced martensite transformation of the retained β phase under deformation. 2,8,9) This result indicates that the combination of strength and ductility of Ti-6Al-4V alloy can be further improved by retained β phase, even for a short time.…”