真空浸渗C_(sf)/AZ91D复合材料的高温变形行为与机理  

Hot Deformation Behavior and Mechanism of C_(sf)/AZ91D Composites Fabricated by Vacuum Pressure Infiltration Method

作　　者：尚鸿甫 王振军[1] 黄飚[1] 朱世学[1] 余欢[1] 

机构地区：[1]南昌航空大学轻合金加工科学与技术国防重点学科实验室

出　　处：《特种铸造及有色合金》2016年第8期856-860,共5页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51365043);江西省自然科学基金资助项目(20151BAB206004);西北工业大学凝固技术国家重点实验室开放基金资助项目(SKLSP201228);南昌航空大学轻合金加工科学与技术国防重点学科实验室开放基金资助项目(GF201301007)

摘　　要：采用真空辅助压力浸渗法短切碳纤维增强镁基复合材料（Csf/AZ91D）,在变形温度为400~490℃、应变速率为0.001~0.1s-1、最大变形量为50%的条件下,研究了Csf/AZ91D复合材料的高温压缩塑性变形行为,观察了复合材料变形前后的微观组织,通过与基体镁合金对比探讨了镁基复合材料高温塑性变形机理。结果表明,复合材料在高温压缩过程中碳纤维发生了显著的偏转和折断,致使复合材料的应变软化现象较镁合金更为明显;短碳纤维细化了基体组织并增加了界面数量,使得复合材料表现出较高的应变速率敏感性;短碳纤维和晶界对基体强化作用随变形温度升高而减弱,而复合材料应力水平随变形温度增加而显著降低,表现出比镁合金更高的表观变形激活能。The chopped carbon fibers reinforced magnesium composites（Csf/AZ91Dcomposite）were prepared by vacuum assisted pressure infiltration method.The hot deformation behavior of Csf/AZ91 Dcomposites prepared was investigated at 400~490 ℃ and strain rate of 0.001~0.1s-1 as well as maximum deformation strain of 50%.The microstructure of the composites before and after deformation was observed by optical microscope,and the hot plastic deformation mechanism of the composites prepared was approached by comparing with the magnesium alloy.The results indicate that the strain softening of the composites prepared is the more significant than that of the corresponding magnesium alloy due to the rotation and breakage of whiskers during hot compression process.The matrix microstructure is refined by the chopped carbon fibers during fabrication,and the quantity of interface including grain boundary and phase interface is increased accordingly.As a result,the composites prepared exhibit a high strain rate sensitivity.In addition,the strengthening effect of short carbon fiber and grain boundary is weaken,and the stress level of the composites is decreased significantly with the increase of the deformation temperature.The apparent deformation activity energy of the composites is the higher than that of the corresponding magnesium alloy.

关 键 词：Csf/AZ91D复合材料 高温变形 流动应力 变形机理 

分 类 号：TB33[一般工业技术—材料科学与工程]