(1. 西北工業(yè)大學(xué) 材料學(xué)院，西安 710072；
2. 上海市寶鋼股份有限公司 特殊鋼分公司，上海 200940)
摘 要: 對(duì)具有片層α相的BT25合金圓餅在兩相區(qū)進(jìn)行4種變形程度的等溫鍛造，用定量金相分析方法研究變形量對(duì)顯微組織特征參數(shù)(α相體積分?jǐn)?shù)、α片層厚度和α相球化率)的影響規(guī)律。結(jié)果表明：隨著變形量增加，α片層不斷彎曲破碎，導(dǎo)致α片層長寬比減小而球化率增大，當(dāng)變形量達(dá)到80%時(shí)球化率為85.23%，改善了合金組織的均勻性；在變形過程中片層α兩端的物質(zhì)向中間擴(kuò)散，導(dǎo)致片層厚度增加，變形量從0%增至80%，α片層厚度增加了1.6 μm；α相的體積分?jǐn)?shù)由于等溫鍛造溫度不變而基本維持在60%左右，大變形時(shí)有所降低。
關(guān)鍵字: BT25合金; 定量金相; 顯微組織參數(shù); 變形量
（1. School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China;
2. Special Steel Branch Company, Shanghai Baoshan Iron & Steel Co., Ltd., Shanghai 200940, China）
Abstract:The isothermal compression of BT25 titanium alloy with initial lamellar was carried out with four deformation degrees and the effect of deformation degree on microstructure parameters (volume fraction, thickness and globularization ratio of α phase) was investigated based on quantitative metallography. The results show that the process of α lamellar pinch-off/fragmentation takes place with increasing the deformation degree, which results in the decrease of the Feret ratio of α lamellar and the increase of globularization ratio. It reaches 85.23% when the deformation degree is 80%. The microstructure homogeneity of the alloy is improved. Mass diffusion from both ends of α lamellar to center happens during the deformation process, making the thickness of α phase increase (about 1.6 μm with increasing deformation degree from 0% to 80%). The volume fraction of α phase (about 60%) remains unchanged because of a stable deformation temperature. However, it decreases slightly in the case of high forging strains.
Key words: BT25 titanium alloy; quantitative metallography; microstructure parameter; deformation degree
