(1. 北京有色金屬研究總院 加工工程研究中心，北京 100088；
2. 上海交通大學(xué) 金屬基復(fù)合材料國(guó)家重點(diǎn)實(shí)驗(yàn)室, 上海 200030)
摘 要: 在Gleeble−1500D熱模擬機(jī)上采用等溫壓縮實(shí)驗(yàn)，研究原位合成TiB2/6351復(fù)合材料在變形溫度為300~ 550 ℃和應(yīng)變速率為10−3~10 /s條件下的流變變形行為。結(jié)果表明：在實(shí)驗(yàn)范圍內(nèi)，該復(fù)合材料高溫壓縮時(shí)均存在穩(wěn)態(tài)流變特征且屬于正應(yīng)變速率敏感材料；在低應(yīng)變速率和較高溫度條件下, 隨變形程度的增加，流變應(yīng)力增加到峰值后緩慢下降，逐漸趨于平穩(wěn)，呈現(xiàn)明顯的動(dòng)態(tài)再結(jié)晶特征；而在較高應(yīng)變速率和較低溫度下，呈現(xiàn)明顯動(dòng)態(tài)回復(fù)特征；可用包含Arrhenius項(xiàng)的Zener-Hollomon參數(shù)描述TiB2/6351復(fù)合材料高溫壓縮流變行為。通過線性回歸分析和優(yōu)化計(jì)算，得出流變應(yīng)力σ解析表達(dá)式中A、α和n分別為3.52×1010 /s、0.023 MPa−1和7.33，其熱變形激活能Q為170.10 kJ/mol。
關(guān)鍵字: 原位TiB2/6351復(fù)合材料；熱壓縮變形；流變應(yīng)力；Zenner-Hollomon參數(shù)；熱變形激活能
（1. Processing Engineering Research Center, General Research Institute for Nonferrous Metals, Beijing 100088, China;
2. State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, Shanghai 200030, China）
Abstract:The flow stress features of in-situ TiB2/6351 composites were studied by isothermal compression at 300− 550 ℃ and strain rate of 10−3−10 /s on Gleeble−1500D system. The results show that TiB2/6351 composites have the steady-state flow characteristics and belong to positive strain rate sensitized materials during hot compression deformation. At lower strain rates and higher temperatures，with the increase of strain， the flow stress increases to peak value and then falls down, at last tends to smooth gradually. The curves express the feature of dynamic recrystallization. But at higher strain rates and lower temperatures, dynamic recovery occurs obviously. The flow stress of in-situ TiB2/6351 composites during high temperature compression deformation can be represented by Zener-Hollomon parameter including Arrhenius term. A, α and n in the analytical expressions of flow stress are 3.52×1010 /s, 0.023 MPa−1 and 7.33, respectively, by linear regression analysis and optimization calculation. The hot deformation activation energy of TiB2/6351 composites during hot deformation is 170.10 kJ/mol.
Key words: in-situ TiB2/6351 composite; hot compression deformation; flow stress; Zener-Hollomon parameter; deformation activation energy
