SiC对泡沫镁合金组织和性能的影响

Effects of SiC on Microstructure and Properties of Foamed Magnesium Alloy

对采用白云石作为发泡剂、SiC作为增粘剂制备的泡沫镁合金进行了微观表征和压缩测试,考察了SiC加入量对泡沫镁合金压缩性能和吸能性能的影响。结果表明,白云石作为发泡剂,在泡沫镁合金制备过程中并不能完全分解,未分解白云石及其分解和反应产物在孔壁处基本均匀分布,在内孔边缘局部聚集;增粘剂SiC在泡沫镁合金中以颗粒物的形式存在,主要聚集于内孔边缘及孔壁组织晶界位置。SiC含量在5%~20%内时,随着SiC加入量的增加,泡沫镁合金的密度、压缩平台应力和单位体积内吸收的能量均呈现出先减小后增大的趋势,转折点SiC含量为10%。在应变量为0~1内,泡沫镁合金的能量吸收效率随着应变量的增加先迅速升高,随后在一定范围内波动,最后迅速下降,波动范围为0.1~0.6。SiC加入量对泡沫镁合金能量吸收效率的影响规律不明显。

The micro-characterization and compressive tests of foamed magnesium alloys prepared with dolomite as foaming agent,SiC as tackifier were carried out,and effects of tackifier on the compressive properties and energy absorption of the alloy were investigated.The results reveal that the dolomite presents the un-complete decomposition as foaming agents for preparing foamed magnesium alloy.The undecomposed dolomite and its decomposition and reaction products are distributed uniformly in the pore wall and agglomerated locally at the edge of the inner pore.The tackifier SiC is agglomerated at the edge of the inner hole and the grain boundary of the pore wall structure in form of particulate in foamed magnesium alloy.Within the range of 5%~20%,with the increase of tackifier SiC content,the density,the platform stress and the absorbed energy per unit volume all shows a trend of decreases at first and then increases.The turning point is 10%.Within the range of strain of 0.1~0.6,with the increase of strain,the energy absorption efficiency of foamed magnesium alloy is increased rapidly at first,and then fluctuated up and down within a certain range,finally decreased rapidly.The fluctuation region is 0.1~0.6.The effects of SiC content on the energy absorption efficiency of foamed magnesium alloy can be ignored.