采用Bridgeman定向凝固设备成功制备了Ti-48Al-8Nb(原子分数,％)合金定向凝固试样,分析了不同抽拉速度对柱状晶形貌及过渡区、稳态区和淬火区凝固组织的影响.实验结果表明:在不同抽拉速度下,柱晶沿抽拉方向生长良好,柱状晶内部片层取向一致,与生长方向呈45°、90°夹角;当抽拉速度为8μm/s时,固液界面以胞状形貌向前推进,抽拉速度增大到15μm/s时固液界面开始向树枝状生长转化,随着抽拉速度进一步增大,二次枝晶间距逐渐变小,组织明显细化,片层间距显著减小;组织中与生长方向垂直的片层组织所占比例随抽拉速度增大而增加.
参考文献
| [1] | Takeyama M.;Yamamoto Y.;Morishima H.;Koike K.;Chang SY.;Matsuo T. .Larnellar orientation control of Ti-48AlPST crystal by unidirectional solidification[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2002(0):7-12. |
| [2] | Rainer Gerling;Arno Bartels;Helmut Clemens .Structural characterization and tensile properties of a high niobium containing gamma TiAl sheet obtained by powder metallurgical processing[J].Intermetallics,2004(3):275-280. |
| [3] | H. Saari;J. Beddoes;D.Y. Seo .Development of directionally solidified gamma-TiAl structures[J].Intermetallics,2005(9):937-943. |
| [4] | Kim HY.;Wegmann G.;Maruyama K. .Effect of stress axis orientation on the creep deformation behavior of Ti-48Al polysynthetically twinned (PST) crystals[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2002(0):795-801. |
| [5] | G.L. Chen;X.J. Xu;Z.K. Teng .Microsegregation in high Nb containing TiAl alloy ingots beyond laboratory scale[J].Intermetallics,2007(5/6):625-631. |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%