表面处理对钢-铝双金属铸件组织性能的影响

Effects of Surface Treatment on Microstructure and Properties of Steel-Aluminum Bimetal Casting

采用未浸表面改性剂直接热浸铝、浸表面改性+热浸铝两种不同的表面处理工艺分别对钢基体外表面进行处理,利用镶铸法制备钢-铝双金属复合材料,研究了复合铸件铸态和T6态的界面组织和结合性能。结果表明,直接浸铝铸件在Fe-Al交界处存在缝隙,未形成冶金结合层,其界面结合情况较未处理铸件有所改善,界面结合力提高了21.23%,达到60.30kN,缝隙率降至10.99%;改性+浸铝铸件存在Fe-Al、Al-Al两种界面,在Fe-Al界面处出现"锯齿状"冶金过渡层,界面剪切强度较直接浸铝铸件提高13.85%以上,缝隙率降至2.93%。改性+浸铝铸件T6热处理后,过渡层厚度明显增加,"锯齿"平均长度由31μm增至46μm,且过渡层成分逐渐均匀化,界面结合力增至79.71kN。

Steel-Aluminum compound materials were fabricated by inlay casting with un-modification ＆amp;hot-dip aluminizing（U＆amp;H）and surface modification ＆amp;hot-dip aluminizing（S＆amp;H）treated steel as sub-strates ,and the as-cast and T6 heat treatment microstructures and bonding properties of Fe/Al inter-face were investigated.The U＆amp;H casting samples reveal that a variety of gaps exist and metallurgical bonding is absent at the Fe-Al interface.Compared with untreated ones,the interfacial combination of U＆amp;H castings is improved,where the bonding force reaches 60.30 kN,increased by 21.23% ,and the gap rate is reduced to 10.99% .However,the composite casting samples with S＆amp;H treatment reveal the satisfied interface properties with two kinds of interfaces including Fe-Al and Al-Al.The occurrence of“zigzag-shape”transition layer at the Fe-Al interface indicates the existence of metallurgical bonding. Compared with those of U＆amp;H castings,the interfacial bonding strength of casting with S＆amp;H treatment is improved by more than 13.85% and the gap rate is reduced as low as 2.93% .After T6 heat treatment of S＆amp;H modified castings,the thickness of transition layer is increased significantly,especially the“zig-zag”whose average length is increased from 31μm to 46μm.And the composition of transition layer is more homogeneous,improving the interfacial force up to 79.71 kN.