金属泡沫断裂韧性的试验研究  

Experimental investigation on fracture toughness of metal foam

作　　者：王新筑[1,2,3] 周雄[3] 朱炳杰[4] 彭向和[3] 

机构地区：[1]吉林大学汽车仿真与控制国家重点实验室,吉林长春130025 [2]湖南大学汽车车身先进设计制造国家重点实验室,湖南长沙410082 [3]重庆大学航空航天学院,力学博士后工作站,非均质材料力学重庆市重点实验室,重庆400040 [4]国防科技大学航天科学与工程学院,湖南长沙400040

出　　处：《国防科技大学学报》2016年第4期174-178,共5页Journal of National University of Defense Technology

基　　金：汽车仿真与控制国家重点实验室开放基金资助项目(20121110);汽车车身先进设计制造国家重点实验室开放基金资助项目(31315010);中央高校基本科研业务费资助项目(CDJZR14325501);中国博士后基金面上资助项目(2011M500067)

摘　　要：金属泡沫在其实际应用中,断裂性能和断裂韧性对于承载的多孔金属泡沫有着重要的意义。基于美国试验材料学会相关标准,采用三点弯曲试样测定了铝泡沫的I型断裂韧性。研究表明,金属泡沫的断裂为脆性断裂,在裂纹尖端附近,孔壁最薄弱的区域最容易发生变形;随着进一步加载,一些孔壁发生断裂,微裂纹在断裂尖端附近出现。随着载荷的增加,主裂纹在缺口根部形成或由微裂纹合并而成,并开始在多孔结构内传播。裂纹沿着结构最薄弱处传播,并产生次生裂纹和裂纹桥。裂纹总的扩展方式还是I型断裂。根据试验P-V曲线特点,取最大载荷点对应的力与位移求解出铝泡沫的裂纹尖端临界张开位移的平均值为0.051 mm。In practical applications, fracture properties and fracture toughness of porous metal foam for bearing are very important. Based onASTM standards, three-point bending of aluminum foam samples was used to determine I type fracture toughness. It is shown that the fracture of metal foam is brittle fracture. The deformation is localized in the thinnest regions of the cell walls surrounding the crack tip. With further loading, some cell walls existed fracture phenomenon and microcracks appear in the vicinity of the crack tip. With the increasing of load a main crack is initiated at the notch root or at the pre-crack by a coalescence of microcracks, and starts to propagate through the cell structure. The crack follows the weakest path through the structure and creates the secondary cracks and crack bridges. The main way of crack extension is I type fracture. According to the P - V curve characteristics, taking the force and displacement of the maximum load point to calculate the critical crack tip opening displacement, the average crack-tip opening displacement is 0. 051mm.

关 键 词：金属泡沫 断裂韧性 三点弯曲 裂纹尖端张开位移 

分 类 号：V252[一般工业技术—材料科学与工程]