摘要
对采用熔体发泡法制造的不同密度泡沫铝进行了准静态压缩试验、拉伸试验和弯曲试验。结果表明,泡沫铝的压缩特性曲线包括线弹性变形区、平台区和密实化区。试样的高宽比H/D明显影响压缩应力-应变曲线。当H/D较小时,平台应力曲线较平滑;当H/D较大时,平台应力曲线剧烈波动,呈显著的锯齿状。且在试样中间部位出现与加载轴线呈25°—45°的剪切带。拉伸和弯曲过程中,泡沫铝应力快速增加,当达到应力峰值即屈服点后急剧减小,在最终破断失效前,没有明显的屈服变形带。压缩坪应力Rpl、拉伸屈服应力RUTS和冷弯屈服应力Rf随密度的增加而增加。
Quasi-static compression tests,tensile tests and bending tests were carried out to study the mechanical properties of the closed-cell aluminum foam in the porosity range of 72% —93%,which was manufactured by melt transferring-foaming process. Results indicate that the compression curve of aluminum foam,including linear elastic zone plateau zone and densification zone; the compress behavior is influenced by the ratio of height（ H） / extent（ D） of specimens. The plateau stresses are roughly constant with increasing strain until the densification occurs,when H / D is less than 1. 4. The stress plateau is serrated,as is typical of brittle foam： the serrations correspond to fracture of cell walls,when H / D is greater than 1. 4; and it emerges shearing zone,which is 25°—45° with the loading axis in the middle of samples. The procedure of Al-foam under tensile and bending presents that the stress rapidly increases,then flutteringly fades when it reach up to the peak stress. There is not visible yielding zone before fracture finally. The compressive flow strength Rpl,tensile yield stress RUTSand bending yield stress Rfall raise with increasing density.
出处
《材料开发与应用》
CAS
2014年第6期38-43,共6页
Development and Application of Materials
关键词
泡沫铝
压缩
拉伸
冷弯
变形机制
close-celled aluminum foams
quasi-static compression
tensile
bending
deformation mechanism
