反应合成Ti-35%Al多孔合金的膨胀特性

Swelling Behavior of Porous Ti-35%Al Alloy Prepared by Reactive Synthesis

烧结膨胀特性是元素粉末反应合成Ti-Al合金多孔材料的重要特征,与其孔结构性能密切相关。本文在其它制备参数一定的条件下,从普通反应合成和约束烧结二个过程分别论述Ti-Al合金多孔材料的膨胀行为及其规律。结果表明:Ti/Al元素的溶解度和扩散速率的差异导致Kirkendall孔隙的产生,引起了坯体体积的大幅度膨胀。在Al的第一阶段偏扩散过程中,Ti-Al烧结坯发生了高达60%以上的大幅度体积膨胀行为,同时坯体的开孔隙度接近40%;在Al的第二阶段偏扩散过程中,Ti/Al烧结坯的体积膨胀量为1%-3%,同时坯体的开孔隙度达到47%左右。而在约束烧结过程中,Ti-Al合金多孔材料的前期膨胀行为表现出严格的直线变化规律;在烧结后期,Ti-Al合金多孔材料表现出体积略为收缩的行为。

Swelling behavior is an important feature of Ti-AI alloy porous material prepared by reactive synthesis of element powder as raw material,and closely related with its pore structure properties. The influences of reactive synthesis process and restrained sintering on swelling behavior of Ti-AI alloy porous material were investigated thoroughly and detailedly under the given condition of other preparing parameters.The results show Kirkendall pores formed due to the discrepancies of Ti/Al solubility and diffusion rates lead to the wide-range expansion of compact volume.In the first stage of Al diffusion, Ti-AI compact appears volume expansion behavior of more than 60%and near 40%of open porosity;in the second stage of Al diffusion,Ti-AI compact occurs volume expansion of 1%-3%with open porosity of 47%.In earlier stage sintering procedure,swelling behavior of Ti-AI alloy porous material through restrained sintering shows strict linear law;in final sintering procedure,it shows a little shrinkage behavior of volume.