用急冷Al基合金作中间层对Si_3N_4进行扩散焊连接的研究

RESEARCH ON DIFFUSION BONDING OF Si_3N_4 USING RAPIDLY SOLIDIFIED Al-BASED INTERLAYER

本文研制了急冷及普通Al基中间层材料,并对其性能及其在对Si_3N_4陶瓷进行扩散焊时用作中间层进行了研究。结果表明:Al基中间层经急冷凝固处理后组织细小,成分均匀,硬度高,熔点低。接头的剪切强度试验结果表明:在同一扩散焊工艺条件下,急冷中间层接头的剪切强度明显高于普通中间层接头的剪切强度。其中急冷Al-Si-In-Ti-Zn-Mg中间层接头在扩散焊温度为475℃时(保温时间30min,压力为15MPa),强度最高(50MPa)。随着扩散焊温度的提高,接头剪切强度明显下降。断口分析表明:接头均断在界面附近。界面附近的富In相是接头强度的薄弱环节。随着扩散焊温度的提高,富In相尺寸增大,接头强度下降。急冷Al基中间层扩散焊连接Si_3N_4陶瓷的机制是:活性元素Ti向界面扩散富集并与Si_3N_4发生化学反应,生成界面相TiN,同时中间层中的Al也向界面富集并与Si_3N_4发生化学反应,生成AIN界面相。

In this poper, a new rapidly solidified(RS)Al-based interlayer material has been developed. The properties of this interlayer and the diffusion bonding of Si_3N_4 with it have been investigated. The results show that: After rapid solidification, the Al-based interlayer has smaller grain, more homogeneous composition, lower melting point and higher hardness. At the same diffusion bonding parameter, the shear strength of joint using RS Al-based interlayer is remarkably higher than that of using normally solidified (NS)Al-based interlayer. The max shear strength of the joint with RS Al-based interlayer is 50MPa,at the diffusion bonding parameters of 475℃×30min×15MPa. With the increase in temperature of diffusion bonding, the shear strength of joint decreases remarkably. The result of fracture analyzing shows that: All joints are broken near by the interface. The In-rich phase on the interface is the weak region of joint. With the in crease in temperature of diffusion bonding, the size of In-rich phase increases and the strenhth of joint decreases. The joining mechanism of diffusion bonding of Si_3N_4 using RS Al-based interlayer is that: Ti and Al diffuse toward interface、react with Si_3N_4 and form TiN、AlN ere interface phases.