Effects of Stress Relief Heat Treatment Process on Thermal Analysis and Kinetics of Ti-6Al-4V Alloys
SAMPE 2026 Conference and Exhibition, Washington, Amerika Birleşik Devletleri, 27 - 30 Nisan 2026, ss.714-721, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Doi Numarası: 10.33599/nasampe/s.26.160
- Basıldığı Şehir: Washington
- Basıldığı Ülke: Amerika Birleşik Devletleri
- Sayfa Sayıları: ss.714-721
- Anahtar Kelimeler: Cryogenic Treatments, Phase Transformation, Physical Property, Stress Relief, Ti-6Al-4V
- Gazi Üniversitesi Adresli: Evet
Özet
In this study, Ti-6Al-4V alloys were produced using a 3D metal printing process (EOS M290), and their weight change/oxidation (thermogravimetric analysis - TGA) properties were investigated at different processing speeds. After production by layered manufacturing, the printed samples were subjected to stress relief treatment at 700°C for 2 hours. Thermogravimetric analysis (TGA) results of both the as-printed and stress-relieved samples showed an increase in mass values in all samples, starting at approximately 400°C and becoming more pronounced between 600 and 800°C. When the thermodynamic enthalpy and activation energy of these temperature-dependent phase transformations were calculated, it was observed that the stress relief process caused chemical and physical changes in the materials. After stress relief heat treatment, martensite transforms into the more stable α+β phase. Since the defect density decreases, the diffusion rate of oxygen slows down, and the mass increase was found to be 10% less than in the as-printed case. The activation energy, calculated using the Kissinger equation, was found to be 50% lower compared to the stress-relieving heat treatment of the as-printed sample. This indicates that the energy required to initiate the change is easier. Due to the martensite in its microstructure and high dislocation density, the low activation energy also proved, via SEM images, that it is much more unstable to thermal effects. The test results provide an important information for understanding how stress-relieving heat treatment affects the temperature, oxidation resistance, and phase transformation behavior of Ti-6Al-4V alloys produced via doping methods.