Influence of the final temperature of investment healting on the tensile strength and Vickers hardness of CP Ti and Ti-6Al-4V alloy

Abstract

The aim of the work was to evaluate the influence of the temperature of investment healting on the tensile strength and Vickers hardness of CP Ti and Ti-6Al-4V alloy casting. Were obtained for the tensile strength test dumbbell rods that were invested in the Rematitan Plus investment and casting in the Discovery machine cast. Thirty specimens were obtained, fiftten to the CP Titanium and fifteen to the Ti-6Al-4V alloy, five samples to each an of the three temperatures of investment: 430°C (control group), 480°C and 530°C. The tensile test was measured by means of a universal testing machine, MTS model 810, at a strain of 1.0 mm/min. After the tensile strenght test the specimens were secctioned, embedded and polished to hardness measurements, using a Vickers tester, Micromet 2100. The means values to tensile tests to the temperatures 430°C, 480 and 530: CP Ti (486.1 – 501.16 – 498.14 –mean 495.30 MPa) and Ti-6Al-4V alloy (961.33 – 958.26 – 1005.80 – mean 975.13 MPa) while for the Vickers hardness the values were (198.06, 197.85, 202.58 – mean 199.50) and (352.95, 339.36, 344.76 – mean 345.69), respectively. The values were submitted to Analysis of Variance (ANOVA) and Tukey,s Test that indicate differences significant only between the materials, but not between the temperature, for both the materias. It was conclued that increase of the temperature of investment its not chance the tensile strength and the Vickers hardness of the CP Titanium and Ti-6Al-4V alloy.

Volume magnetic susceptibility design and hardness of Au–Ta alloys and Au–Nb alloys for MRI-compatible biomedical applications

“…Under the condition of y=15, equation (7b) yields equation (14): Substitution of equations ( 3) and ( 14) into (9b) yields equation ( 16): Equation (25) shows the dependence of the minimum χ v value after the saturation of aging at 800 °C on the Nb content of Au-yNb alloys, as observed in figure 5. χ v of Au-12Nb after aging at 800 °C for 100 h is close to the calculated minimum value; therefore, the aging was nearly saturated after 100 h. Equation (13a) indicates that the maximum χ v value of Au-yNb alloys (y>6.8) is larger than −9 × 10 −6 and equation (25) indicates that the minimum χ v value of Au-yNb alloys (y>6.8) after saturation of aging at 800 °C is less than −9 × 10 −6 . Therefore, Au-yNb alloys (6.8<y<19) are possible candidates for MRI-compatible alloys after optimizing the χ v value by aging.…”

“…The authors have developed MRI-compatible Au-Pt-Nb alloys that succeeded in improving the hardness of Au-Pt alloys [24]. The Vickers hardness (HV) of the alloy was 193 HV after aging treatment; this value corresponded to that of CP-Ti (198 HV, Grade 2 [25]) but was much lower than that of Ti alloy (353 HV, Ti-6Al-4V (in mass%) alloy [25]). For some types of biomedical devices fabricated from Ti alloys, alloys with higher HV are required.…”