Vickers hardness of cast commercially pure titanium and Ti-6Al-4V alloy submitted to heat treatments

Abstract

The purpose of this study was to evaluate the effect of heat treatments on the Vickers hardness of commercially pure titanium and Ti-6Al-4V cast alloys. Six-millimeter-diameter cylindrical specimens were cast in a Rematitan System. Commercially pure titanium and Ti-6Al-4V alloy specimens were randomly assigned to 3 groups (n=10) that received the following heat treatments: control (no heat treatment); treatment 1 (T1): heating at 750 degrees C for 2 h; and treatment 2 (T2): annealing at 955 degrees C for 1 h and aging at 620 degrees C for 2 h. After heat treatments, the specimens were embedded in acrylic resin and their surface was ground and polished and hardness was measured. Vickers hardness means (VHN) and standard deviations were analyzed statistically by Kruskal-Wallis test at 5% significance level. For commercially pure titanium, Vickers hardness means of group T2 (259.90 VHN) was significantly higher than those of the other groups (control--200.26 VHN and T1--202.23 VHN), which presented similar hardness means to each other (p>0.05). For Ti-6Al-4V alloy, statistically significant differences were observed among the three groups: T2 (369.08 VHN), T1 (351.94 VHN) and control (340.51 VHN) (p<0.05). The results demonstrated different hardness of CP Ti and Ti-6Al-4V when different heat treatments were used. For CP Ti, VHN means of T2 group was remarkably higher than those of control and T1 group, which showed similar VHN means to each other. For Ti-6Al-4V alloy, however, VHN means recorded for each group may be presented as follows: T2>T1>control.

Impact of ruthenium on microstructure and corrosion behavior of β-type Ti–Nb–Ru alloys for biomedical applications

“…5(b). cast CP Ti in literature in a similar as-cast state, which even after significant heat treatment, rises at most to 260 Hv, though this is of course still less than the values observed for common α+β duplex alloys such as Ti-6Al-4V, at 341-369 Hv [20,21]. It also closely matches that seen for similar Ti-35Nb (wt.%) alloy recently reported by Griza et al, where hardness is attributed to α″ formation [22].…”

The Microstructural Revolution of Ti-6Al-4V Specimens Fabricated by Selective Laser Sintering of Pre-alloyed Powders

“…The asbuilt samples show a great variation in Vickers microhardness (~350 ÷ 390 Hv). However, most of them are higher than that of conventional products (~340 ÷ 350 Hv) [12,20,21]. It seems that the high speed of laser scanning resulted in low hardness value that the samples got.…”

Preparation and characterization of alloys of the Ti–15Mo–Nb system for biomedical applications

“…These developed alloys have a microhardness greater than grade 2 cp‐Ti (200 HV) and 316 L stainless steel (195 HV), which are both widely used materials for biomedical applications; when niobium is added, the values become closer to that characteristic of those materials. On the other hand, other alloys for biomedical applications, such as Ti–6Al–4V (340 HV) and CoCrMo (543 HV), which have higher microhardness values than the studied alloys, showing that the developed materials are promising for biomedical applications.…”