(1. 河南科技大學(xué) 材料科學(xué)與工程學(xué)院，洛陽(yáng) 471003；
2. 河南省有色金屬材料科學(xué)與加工技術(shù)重點(diǎn)實(shí)驗(yàn)室，洛陽(yáng) 471003)
摘 要: 采用真空熱壓-內(nèi)氧化燒結(jié)方法制備20%Mo/Cu-Al2O3復(fù)合材料，測(cè)試其性能并觀察分析其微觀組織。利用Gleeble-1500D熱力模擬試驗(yàn)機(jī)在溫度為350~750 ℃、應(yīng)變速率為0.01~5 s-1及總應(yīng)變量0.5的條件下，對(duì)20%Mo/Cu-Al2O3復(fù)合材料熱變形過(guò)程中的流變應(yīng)力與應(yīng)變之間的關(guān)系進(jìn)行研究。結(jié)果表明：20%Mo/Cu-Al2O3復(fù)合材料的組織分布均勻，未觀察到明顯的團(tuán)聚現(xiàn)象及孔洞，致密度較高。在材料基體上，原位內(nèi)氧化生成的納米級(jí)Al2O3顆粒呈彌散分布，增加了基體的強(qiáng)度。復(fù)合材料的高溫流動(dòng)應(yīng)力—應(yīng)變曲線以動(dòng)態(tài)再結(jié)晶軟化機(jī)制為主，峰值應(yīng)力隨變形溫度的降低或應(yīng)變速率的升高而增加；在真應(yīng)力—真應(yīng)變曲線基礎(chǔ)上建立的高溫變形本構(gòu)方程較好地表征了此復(fù)合材料的高溫流變特性，其計(jì)算結(jié)果與實(shí)驗(yàn)結(jié)果吻合較好。
關(guān)鍵字: 20%Mo/Cu-Al2O3復(fù)合材料；強(qiáng)化；熱變形；動(dòng)態(tài)再結(jié)晶；本構(gòu)方程
（1. School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China;
2. Henan Key Laboratory of Advanced Non-Ferrous Materials, Luoyang 471003, China）
Abstract:The 20%Mo/Cu-Al2O3 composites were prepared by vacuum-pressed in situ internal oxidation sintering, their properties and microstructures were tested and observed, respectively. Using the Gleeble-1500D thermal simulator, the relationship between the flow stress and strain during the hot deformation process of the 20%Mo/Cu-Al2O3 composites was investigated at temperature of 350-750 ℃, strain rate of 0.01-5 s-1 and total strain of 0.5. The results show that the microstructures of the 20%Mo/Cu-Al2O3 composites well distribute, no aggregate phenomena and holes are observed, and the density is relatively high. The in situ internal oxidation generated nano Al2O3 particles distribute dispersively, which enhances the body strength of the composites. The softening mechanism of dynamic recrystallization of the composites is a feature for the high-temperature flow stress—strain curves of the composite, and the peak stress increases with the decrease of deformation temperature or the increase of strain rate. Based on the true stress—true strain curves, the established constitutive equation represents the high-temperature flow behavior of the composite, and the calculated results of the flow stress are in good agreement with the experimental results of the high-temperature deformation.
Key words: 20%Mo/Cu-Al2O3 composite; strengthening; hot deformation; dynamic recrystallization; constitutive equation
