纤维增强冰模板氧化铝多孔陶瓷的微观结构与力学性能

Microstructure and Mechanical Properties of Fiber-reinforced Ice-templated Alumina Porous Ceramics

采用定向冷冻冰模板法制备了具有定向直通孔结构的纤维增韧氧化铝多孔陶瓷以及纯颗粒氧化铝多孔陶瓷,研究了固含量和纤维引入对材料微观结构及力学性能的影响。结果表明:随着固含量从15%(体积分数)提高至40%,材料的微观形貌从层状孔到枝状孔再到各向同性孔变化,层间距逐渐减小直到消失;材料的强度从7 MPa提高至70 MPa;纤维的引入增大了层间距并在层状孔壁间形成桥联,从而降低了材料的密度;在低固含量时,纤维的引入改变了直通孔多孔材料的应力应变行为,形成应力平台区,使得冰模板多孔陶瓷从脆性断裂转变为渐进式断裂,材料的抗压强度和断裂能量吸收能力提高。

Fiber-reinforced alumina porous ceramics and pure granular alumina porous ceramics with directional pores were prepared by an ice-templated method,and the effects of solid loading and addition of fibers on the microstructure and mechanical properties of the porous ceramics were investigated.A transition from lamellar to dendritic and then to isotropic and a gradually decrease of lamellar spacing are trigged at an increased solid loading.The compressive strength increases from 7 to 70 MPa with the increase of solid loading from 15%(in volume)to 40%.In addition,the addition of fibers also leads to the increase of toughness,strength and energy absorption capacity of ice-templated porous ceramics and changes the fracture behavior from brittle fracture to graceful progressive failure.