热压合成Ti_4AlN_3及其物理性能研究

Research on the Synthesis and Physical Properties of Ti_4AlN_3 by Hot-pressing

以摩尔比为Ti ◇Al ◇TiN=1 1.2 2.7的混合粉为原料,采用真空热压烧结工艺在1400℃保温2 h成功合成了高纯Ti4AlN3块体材料,Ti4AlN3烧结试样结晶良好,晶粒发育完善,内部较为均匀致密,相对密度达到98.5%,具有较高的抗弯强度(384 MPa)、抗压强度(523 MPa)和断裂韧性(6.5(MPa.m1/2)),较低的维氏硬度(2.9 GPa)和抗破坏能力,具备良好的机械加工性能。Ti4AlN3常温电导率和热导率分别为4.6×105(Ω-1.m-1)和12(W.m-1.K-1),其热导率在25～600℃范围呈上升趋势;25～1100℃的线膨胀系数为9.0×10-6K-1,良好的导热性能和高温热稳定性使其可以应用于高温领域。

Predominantly single-phase bulk samples of Ti4AlN3 was successfully synthesized by a hot-pressing method using blended powders with n（Ti）◇n（Al）◇n（TiN）=1◇1.2◇2.7 as starting materials.The sintered sample was fully dense and well-developed,the relative density of it reaches 98.5%.The Vickers hardness of Ti4AlN3 is low（2.9 GPa） while the flexural strength（384 MPa）,compressive strength（523 MPa） and fracture toughness（6.5（MPa·m1/2）） are relatively high,which make Ti4AlN3 performs well on machinability.The electrical and thermal conductivity of Ti4AlN3 at room temperature are 4.6×105（Ω-1·m-1）and 12（W·m-1·K-1）,the thermal conductivity is increasing at the range of 25 ～600 ℃.The linear expansion coefficient of Ti4AlN3 in 25～1100 ℃ is 9.0×10-6 K-1.Good thermal conductivity and stability at high temperature ensure that Ti4AlN3 can be applied in megathermal fields.