快速升温法制备Ti-Al合金泡沫材料

Fabrication of Ti-Al alloy foam with rapid heating-up technology

利用快速升温法在致密Ti罐或两Ti板夹层中制备Ti-Al合金泡沫夹层材料,通过添加不同量的发泡剂和升温速度控制Ti-Al发泡程度以及孔隙的多少、大小、取向和分布。实验发现:当发泡剂含量大于11%时,开始具有发泡效果,发泡剂含量在13%～15%之间,发泡量、孔径大小和孔径分布比较理想,发泡剂含量大于17%时,形成大孔,且中间的泡最大;当升温速度大于25℃/min时,开始具有发泡现象,随着升温速度继续增加,发泡程度增大,孔隙由少变多,孔径由小变大;当升温速度大于75℃/min时,中间孔隙大部分重合,成大空洞。大量实验发现升温速度是影响孔隙形状、尺寸、取向和分布的主要因素。保温温度和时间是强度大小的主要因素,测试其不同温度下压缩屈服强度,均高于纯钛泡沫材料,具有较高的高温压缩屈服强度。

Using the rapid heating-up technology,the Ti-Al alloy foam was fabricated in the dense Ti alloys tank or between Ti and Ti alloys sheets.Pore shape,size,orientation and distribution were controlled by the different contents of foaming agent and heating-up rate.The results show that,when the blowing agent content is more than 11%,it begins to have a good foaming effect.When the foam agent content is between 13% and 15%,the pore size,foaming volume and pore size distribution are relatively ideal.When the foaming agent content is more than 17%,large holes form and the middle bubble is the biggest.When the heating-up rate is greater than 25 ℃/min,it begins to have a good foaming effect.Increasing the heating-up rate leads to the increase in foam level and pore size.When the heating-up rate is greater than 75 ℃/min,the pores overlap and big holes form in the middle.It is found that the main factor that affects the pore shape,size,orientation and distribution is temperature-rising speed.Compressive yield strength is mainly controlled by the holding temperature and holding time.Compression yield strength of the Ti-Al alloy foam at different test temperatures is higher than that of the pure titanium foam material,indicating the excellent high-temperature compression yield strength of Ti-Al foam.