(北京有色金屬研究總院 有色金屬材料制備與加工國(guó)家重點(diǎn)實(shí)驗(yàn)室，北京100088)
摘 要: 為研究鈦合金的熱壓縮變形過程中流變應(yīng)力、顯微組織等隨變形條件的變化，對(duì)自行研制的Ti-3.0Al- 3.7Cr-2.0Fe低成本鈦合金在Gleeble−1500D 熱模擬實(shí)驗(yàn)機(jī)上進(jìn)行高溫壓縮變形實(shí)驗(yàn)。對(duì)d 8 mm×12 mm的試樣進(jìn)行等溫壓縮變形實(shí)驗(yàn)，研究該合金在變形量為30%、50%和70%(對(duì)應(yīng)真應(yīng)變?yōu)?.2)、變形溫度為800~950 ℃、應(yīng)變速率為0.01~10 s−1條件下的變形行為、流變應(yīng)力的變化規(guī)律以及變形條件對(duì)顯微組織的影響。結(jié)果表明：該合金流變應(yīng)力受變形溫度和應(yīng)變速率影響顯著，流變峰值應(yīng)力隨變形溫度的升高和應(yīng)變速率的降低而降低。采用Arrhenius雙曲正弦模型確定該合金在本實(shí)驗(yàn)條件下的變形激活能Q=214.22 kJ/mol和應(yīng)力指數(shù)n=3.81，并根據(jù)得到的參數(shù)建立相應(yīng)的熱變形本構(gòu)關(guān)系為 =6.91×108[sinh(0.011σ)]3.81exp[−214 220/(RT)]。通過顯微組織觀察發(fā)現(xiàn)，在950 ℃、變形速率≥0.1 s−1時(shí)，發(fā)生再結(jié)晶現(xiàn)象，且隨著變形速率的增加，再結(jié)晶現(xiàn)象越明顯。
關(guān)鍵字: 鈦合金；Ti-3.0Al-3.7Cr-2.0Fe；熱壓縮；本構(gòu)關(guān)系；顯微組織
（State Key Laboratory of Nonferrous Metals and Processes,
General Research Institute for Nonferrous Metals, Beijing 100088, China）
Abstract:In order to study the change of flow stress and microstructures with deformation condition, the hot compressive deformation behavior of self-made Ti-3.0Al-3.7Cr-2.0Fe low cost titanium alloy was investigated by Gleeble−1500D thermal simulator. The test conditions were set as follow, the strain rate ranges from 0.01 s−1 to 10 s−1, the temperature ranges from 800 ℃ to 950 ℃ and the deformation is almost 70% which equal to the true strain of 1.2. The test results indicate that the peak flow stress decreases with the decreasing test temperature and increasing the strain rate. The constitutive relationship of Ti-3.0Al-3.7Cr-2.0Fe alloy is obtained on the base of Arrhenius equations. When the strain rates are higher than 0.1 s−1, the dynamic recrystallization occurs in the alloy, and the higher the strain rates are, the more the evident recrystallization is.
Key words: titanium alloy; Ti-3.0Al-3.7Cr-2.0Fe; hot compressive; constitutive relationship; microstructure
