摘要
采用粉末冶金法制备出Ti-35%Nb泡沫合金,并对该泡沫合金的显微组织,静载力学行为和疲劳特性进行了研究。所制备的泡沫合金组织主要由β-Ti组成,孔洞分布均匀,开孔率高,其压缩曲线表现出典型的开孔泡沫材料的变形特征,孔隙率为66%的TiNb泡沫合金的平台应力约为56MPa,其疲劳强度是15.1MPa(疲劳寿命N=1×107)。疲劳断口分析结果表明微孔和宏孔连接处是容易产生裂纹的地方,裂纹是以塑性疲劳裂纹扩展方式扩展,最终引起了单个孔壁的断裂,从而载荷传递给相邻的孔壁,加速了整个泡沫材料的整体断裂。
The Ti-35% Nb foam alloy was prepared by a powder metallurgy method, and the microstructure and the mechanical properties of the foams under monotonic and cyclic loading were investigated. The microstructure of the foams mainly consisted of 15 Ti phase, and the foams exhibited homogeneous pore distribution with a high open porosity ratio. The stressstrain curves of Ti-35Nb foams presented the typical characters of metallic foams. The plateau stress of the foams with 66% porosity was about 56 MPa and the fatigue strength was 15.1 MPa after 1 × 10^7 cycles. The fractographic analysis of the foams revealed that the cracks nucleated within the struts and grew by a fatigue mechanism, resulted in the fracture of cell walls. Then the loads were transferred to adjacent cell walls, led to the acceleration of failure of whole specimens.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2009年第5期638-643,共6页
Chinese Journal of Rare Metals
基金
国家自然科学基金(50371072)资助项目
关键词
粉末冶金
泡沫合金
平台应力
疲劳性能
powder metallurgy
foam alloy
plateau stress
fatigue property
