浇注温度对消失模铸造固-液复合Al-Mg双合金界面层的影响

Effects of Pouring Temperature on Interface Layers of the Al/Mg Bimetallic Castings Processed by Lost Foam Casting

采用消失模铸造工艺制备了固-液复合Al-Mg双合金,通过光学显微镜(OM)、扫描电镜(SEM)、能谱分析(EDS)和X射线衍射仪(XRD)等研究了浇注温度对Al-Mg双合金界面层的影响。结果表明,随着浇注温度升高,界面层厚度增加。当浇注温度为730℃时,Al-Mg双合金界面层较为致密,且厚度均匀;当浇注温度较低时,Al-Mg双合金界面层存在较多孔隙缺陷;浇注温度较高时,Al-Mg双合金界面层各处厚度不均匀。在不同浇注温度下,Al-Mg双合金铸件界面处都形成了3个不同的反应层,分别是靠近Mg基体侧的Mg17Al12+δ-Mg共晶组织层、中间的Mg_(17)Al_(12)+Mg_2Si层和靠近Al基体侧的Al3Mg2+Mg2Si层。

The Al-Mg bimetallic castings were prepared by lost foam casting（LFC）,and effects of pouring temperature on interface layers of the Al/Mg bimetallic castings processed by lost foam casting were investigated by optical microscopy（OM）,scanning electron microscopy（SEM）,energy-dispersive X-ray spectroscopy（EDS）and X-ray diffractometer（XRD）.The results show that thickness of the interface layer of the Al-Mg bimetal alloy is increased with the increase of the pouring temperature.With a pouring temperature of 730 ℃,a compact and uniform interface layer can be observed.When the pouring temperature is less than 730 ℃,there exist porosity defects in the interface layer of Al-Mg bimetallic castings,while the pouring temperature is more than 730 ℃,the thickness exhibits un-even interface layers of Al/Mg bimetallic castings.At different pouring temperatures,all the interface layers of Al/Mg bimetallic castings are composed of three different reaction layers：the Mg17Al12＋δ-Mg eutectic closed to magnesium,the Mg17Al12＋ Mg2 Si in the interface and the Al3Mg2＋ Mg2Si nearby aluminum.