(北京有色金屬研究總院, 北京 100088)
摘 要: 在Gleeble−1500D熱模擬機(jī)上采用等溫壓縮實(shí)驗(yàn)研究GH625合金的高溫壓縮變形行為，獲得合金在溫度為1 000~1 200 ℃、應(yīng)變速率為10−2~10 s−1的條件下的真應(yīng)力—應(yīng)變曲線，并在考慮摩擦和變形熱效應(yīng)的基礎(chǔ)上對(duì)真應(yīng)力—應(yīng)變曲線進(jìn)行修正。對(duì)修正后的峰值應(yīng)力進(jìn)行線性回歸，得到合金的高溫材料常數(shù)：Q=635.38 kJ/mol, α=0.008 404 MPa−1, n=3.52。通過(guò)非線性回歸建立GH625合金包含應(yīng)變量的高溫變形本構(gòu)模型。在應(yīng)變速率為0.1 s−1時(shí)，隨著熱變形溫度的升高，合金發(fā)生動(dòng)態(tài)再結(jié)晶的體積分?jǐn)?shù)隨之增加，在1 000~1 100 ℃發(fā)生部分動(dòng)態(tài)再結(jié)晶，當(dāng)溫度達(dá)到1 200 ℃時(shí)，發(fā)生完全動(dòng)態(tài)再結(jié)晶，此時(shí)平均晶粒尺寸約為22.21 μm。
關(guān)鍵字: GH625合金; 流變行為; 變形熱; 本構(gòu)模型; 動(dòng)態(tài)再結(jié)晶
microstructure evolution of GH625 Ni-based alloy
（Beijing General Research Institute for Non-ferrous Metals, Beijing 100088, China）
Abstract:The hot deformation behaviors of GH625 nickel-based alloy were investigated by hot compression tests with Gleeble−1500D simulated machine. The true stress—true strain curves in the temperature range of 1 000−1 200 ℃ and strain rate of 10−2−10 s−1 were obtained. The true stain—stress curves were corrected in consideration of the friction and deformation. The material constants, the activation energy (Q) of 635.38 kJ/mol, α of 0.008 404 MPa−1, and n of 3.52, of high-temperature deformation for GH625 were obtained by the linear regression of peak stress. The constitutive equation of GH625 alloy containing the strain was established through non-linear regression. When the strain rate is 0.1 s−1, the volume fraction of dynamic recrystallization increases with increasing the temperature. The results show that partial dynamic recrystallization can be received when the temperature ranges from 1 000 ℃ to 1 100 ℃, and fully dynamic recrystallized structure can be received when the temperature reaches 1 200 ℃. And the average dynamically recrystallized grain size is about 22.21 μm.
Key words: GH625 alloy; flow behavior; deformation heat; constitutive equation; dynamic recrystallization
