(1. 河南科技大學(xué) 材料科學(xué)與工程學(xué)院，洛陽 471023；
2. 有色金屬共性技術(shù)河南省協(xié)同創(chuàng)新中心，洛陽 471023)
摘 要: 采用真空熱壓-內(nèi)氧化燒結(jié)法制備TiC/Cu-Al2O3復(fù)合材料，通過掃描電鏡(SEM)和高分辨率透射電鏡(HRTEM)分析其微觀組織，討論該材料的強(qiáng)化機(jī)理。利用Gleeble-1500D熱力模擬試驗(yàn)機(jī)在溫度為450~850 ℃、應(yīng)變速率為0.001~1 s-1及變形量0.7的條件下進(jìn)行試驗(yàn)。采用加工硬化率處理法對真應(yīng)力-真應(yīng)變數(shù)據(jù)進(jìn)行處理，結(jié)合lnq-e曲線和-？(lnq)/？e-e曲線，確定該材料動(dòng)態(tài)再結(jié)晶臨界條件及動(dòng)態(tài)再結(jié)晶體積分?jǐn)?shù)，并利用該體積分?jǐn)?shù)建立動(dòng)態(tài)再結(jié)晶動(dòng)力學(xué)模型。結(jié)果表明：內(nèi)氧化生成g-Al2O3顆粒的彌散強(qiáng)化作用及TiC與基體間的非晶過渡層提高了材料的強(qiáng)度；該復(fù)合材料熱壓縮過程中存在動(dòng)態(tài)再結(jié)晶軟化；隨著變形量的增加、變形溫度的升高及應(yīng)變速率的降低，動(dòng)態(tài)再結(jié)晶體積分?jǐn)?shù)均增加。
關(guān)鍵字: TiC/Cu-Al2O3復(fù)合材料；強(qiáng)化機(jī)理；熱變形；動(dòng)態(tài)再結(jié)晶
（1. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, China;
2. Collaborative Innovation Center of Nonferrous Metals of Henan Province, Luoyang 471023, China）
Abstract:The TiC/Cu-Al2O3 composite was prepared by vacuum-pressed and internal oxidation sintering. The microstructures were observed and the main strengthening mechanisms were analyzed by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The hot deformation of the composite was investigated by the Gleeble-1500D thermal simulator. The tests were performed at the temperature of 450-850 ℃, the strain rate of 0.001-1 s-1 and the maximum strain of 0.7. According to the ln θ -ε curves and the -？(ln θ)/？ε-ε curves, the critical conditions of dynamic recrystallization and the volume fraction of dynamic recrystallization were obtained by the computation of the work hardening rate (θ) from initial true stress-true stain data. Based on the volume fraction of the dynamic recrystallization of the composite, the dynamic recrystallization kinetic equation was established. The results show that the strength of the composite is enhanced by the dispersion of the g-Al2O3 particles and the amorphous layer between TiC and substrate. There exists the softening mechanism of dynamic recrystallization during the hot compression process. The volume fraction of dynamic recrystallization of the composite increases with the increase of the plastic strain and the deformation temperature, as well as the decrease of the strain rate.
Key words: TiC/Cu-Al2O3 composite; strengthening mechanism; hot deformation; dynamic recrystallization
