The Effect of Heating Rate on Discontinuous Grain Boundary Alpha Formation in a Metastable Beta Titanium Alloy

Abstract

Continuous grain boundary α ($$ \alpha_{\text{GB}} $$ α GB ) is often observed in age-hardened metastable β titanium alloys and plays a detrimental role in ductility. In this work, we show that the heating rate to the aging temperature is crucial in determining the extent of $$ \alpha_{\text{GB}} $$ α GB . The extent of $$ \alpha_{\text{GB}} $$ α GB is determined by the extent of formation of isothermal ω at grain boundaries. This new finding is significant for suppressing continuous $$ \alpha_{\text{GB}} $$ α GB formation in aging hardened β titanium alloys.

Python Tabanlı Destek Vektörü Regresyon Modeli Kullanılarak Farklı Isıtma Hızlarında Yaşlandırılmış β Titanyum Alaşımının Sürtünme Katsayılarının Değerlendirilmesi

“…Öte yandan, daha yavaş bir ısıtma hızı olan 1,9°C/dk gibi bir ısıtma hızında ise α ve ω fazlarının bir arada oluştuğu bir sıcaklık aralığı tespit edilmiştir. Bir diğer çalışmada ise ısıtma hızının Ti-1,5Al-8Mo-3Cr-2,5Fe alaşımında tane sınırı α (αTS) faz oluşumuna etkisi incelenmiştir [7]. Çalışma sonucunda düşük ısıtma hızıyla yaşlandırma işlemi uygulanan numunede αTS fazı oluşumunun baskılandığı görülmüştür.…”

Evolution of Face-Centered Cubic Ti Alloys Transformation by X-ray Diffraction Profile Analysis in Mechanical Alloying

“…Pure Ti has allotropic behavior; below 885 • C, it exhibits a hexagonal close-packed (hcp, called α-phase) crystal structure, and above that, a body-centered cubic (bcc, called βphase) [2,4]. Some metastable phases can be obtained under various heat treatment [12,13], such as casting, welding, or rapid heating/cooling [3,12,14]. The martensitic phases α , α", ω, and phases α n and β n ("n" stands for nonequilibrium composition) are metastable phases in Ti alloys that are formed due to hardening [4,12,13,15].…”

“…Some metastable phases can be obtained under various heat treatment [12,13], such as casting, welding, or rapid heating/cooling [3,12,14]. The martensitic phases α , α", ω, and phases α n and β n ("n" stands for nonequilibrium composition) are metastable phases in Ti alloys that are formed due to hardening [4,12,13,15]. A metastable phase with a face-centered cubic (fcc) crystal structure has been reported by several authors in pure Ti and Ti-based alloys [16][17][18][19][20][21][22][23][24].…”

Comparison of the Microstructure and Mechanical Properties of Ti-3573 and Ti-3873 Alloys after Cold Rolling and Aging Treatment

“…Lightweight is often the goal of a product. With aerospace and automotive industries pursuit of lightweight beta and metastable beta titanium alloy has been studied by many scholars in recent years attribute to high strength-to-weight ratios and excellent fatigue performance [7][8][9]. Favorable processing performance of beta titanium alloy can acquire high strength and target property by old or hot working, solution treatment and aging treatment or other heat treatment processes [8][9][10][11].…”