摘要
对Ｔｂ０３Ｄｙ０７Ｆｅ１９５超磁致伸缩材料定向凝固过程进行了研究和分析，结合ＴｂＤｙＦｅ合金凝固特性，研究了凝固参数（包括定向凝固速率Ｖ和固液界面温度梯度Ｇ）、样品尺寸及起始晶粒取向三个主要因素对ＴｂＤｙＦｅ合金样品轴向取向的影响。当定向凝固参数（Ｇ／Ｖ）控制在适当范围，有利于保持平直的固液界面，因此有利于形成轴向＜１１２＞取向；当Ｖ增大或Ｇ减小，固液界面出现下凹，将影响择优取向的形成。样品尺寸与Ｇ和Ｖ应该相匹配，样品直径太大不利于保持平直的固液界面，因此不利于形成轴向＜１１２＞取向。采用＜１１２＞取向的晶粒作籽晶可以加快晶粒的择优竞争生长过程，有利于形成轴向完全＜１１２＞取向。这些因素的恰当控制，制备出了轴向具有完全＜１１２＞取向的Ｔｂ０３Ｄｙ０７Ｆｅ１９５合金样品，对样品进行高温退火处理，磁致伸缩性能达到了近１７００×１０－６。
The preparation of rare earthiron magnetostrictive material by directional solidification has been made. The directional solidification(DS) parameters(including DS velocity V and temperature gradient G of solidliquid(S/L) interface), the sample′s diameter and the crystal orientation at the initial solidifying stage of the DS processing are three main factors which govern the DS processing stability and the crystal orientation along sample axis. The parameter G/V and the sample′s diameter affect the S/L interface shape and DS processing stability. With decreasing G/V or increasing the sample′s diameter, the flat S/L interface will become concave which leads to preferred orientation tilting from sample axis and unstable DS processing. Seeding crystals can speed up competitive growth of crystals and promote all <112> crystal orientation towards sample axis. In the conditions of an appropriate G/V and relatively small sample diameter, we have prepared the DS Tb03Dy0.7Fe195 alloy with a perfect <112> orientation along sample axis. After high temperature treatment for annealing, the DS samples present magnetostrictive strain about 1700×10-6.
出处
《中国稀土学报》
CAS
CSCD
北大核心
1998年第1期26-30,共5页
Journal of the Chinese Society of Rare Earths
基金
冶金部基础研究基金
