(1. 沈陽工業(yè)大學 材料科學與工程學院，沈陽 110178;
2. 東北大學 軋制技術(shù)及連軋自動化國家重點實驗室，沈陽 110004)
摘 要: 采用熱處理、蠕變性能測試及位錯組態(tài)的衍襯分析，研究熱連軋Ti-6Al-4V合金的蠕變行為及影響因素。結(jié)果表明：經(jīng)低于β相變點的固溶處理，合金的組織結(jié)構(gòu)由高固溶度的等軸α相和網(wǎng)籃組織組成；隨著固溶溫度提高，網(wǎng)籃組織數(shù)量增多；經(jīng)1 000 ℃固溶處理后合金可獲得完全網(wǎng)籃組織；與940 ℃固溶時效合金相比，經(jīng) 1 000 ℃固溶時效合金在420 ℃、575 MPa條件下具有較低的應(yīng)變速率和較長的蠕變壽命；在試驗的溫度和應(yīng)力范圍內(nèi)，計算出該合金的蠕變激活能為249.8 kJ/mol；在蠕變期間，熱連軋合金的變形機制是位錯在具HCP結(jié)構(gòu)的α相中發(fā)生雙取向滑移，940 ℃固溶處理合金的蠕變機制是波浪狀áa+cñ位錯在α相中發(fā)生錐面滑移，而經(jīng)1 000 ℃固溶處理合金的變形機制是(1/2)á111ñ位錯在具BCC結(jié)構(gòu)的β相中發(fā)生多系滑移；經(jīng)1 000 ℃固溶處理合金中所含的高含量富V的β相可提高合金蠕變抗力，這是合金具有較低應(yīng)變速率和較長蠕變壽命的主要原因。
關(guān)鍵字: Ti-6Al-4V合金；熱連軋；固溶處理；蠕變；變形機制
hot continuous rolled Ti-6Al-4V alloy
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110178, China;
2. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110004, China）
Abstract:By heat treatment, measurement of creep properties and contract analysis of dislocations configuration, the creep behaviors and the effect factors of hot continuous rolled (HCR) Ti-6Al-4V alloy were investigated. The results show that, after the alloy solution treated at temperatures lower than β phase transformation point, the microstructures of the alloy consist of the supersaturation equiaxial α phase and network basket structure. The quantities of the network basket structure increase as the solution temperature increases, and the full network basket structure may be obtained after solution-treated at 1 000 ℃. Compared with the alloy solution treated at 940 ℃, the alloy solution treated at 1 000 ℃ displays a lower strain rate and a longer creep lifetime under the conditions of the applied stress of 575 MPa at 420 ℃. In the range of the applied temperatures and stresses, the creep activation energy of the alloy is calculated to be 249.8 kJ/mol. The deformed mechanism of HCR alloy during creep is double orientation slipping of dislocations activated within α phase with HCP structure, while the deformed feature of the alloy solution treated at 940 ℃ is the wave-like áa+cñ dislocations activated on the pyramidal planes in α phase. After solution treated at 1 000 ℃, the deformed mechanism of the alloy is the multiple slipping of (1/2) á111ñ dislocations activated within β phase with BCC structure. In this alloy, the high volume fraction V-riched β phase may enhance the creep resistance of the alloy. This is the main reason why this alloy possesses relatively low strain rate and long creep lifetime.
Key words: Ti-6Al-4V alloy; hot continuous rolling; solution treatment; creep; deformation mechanism
