低W-W连接度65W-25Cu-10Ni合金的制备及其准静态力学性能

Preparation and Quasistatic Mechanical Properties of 65W-25Cu-10Ni Alloy with Low W-W Contiguity

利用W颗粒表面化学镀Ni结合SPS的方法,制备了低W-W连接度65W-25Cu-10Ni合金,并开展了其准静态力学性能研究。结果表明,制得的Ni包W复合粉中,Ni包覆层分布均匀且与W结合良好;以Ni包W复合粉和Cu粉为原料制备的65W-25Cu-10Ni合金的组织均匀且致密。在准静态压缩加载条件下,与65W-35Cu合金相比,65W-25Cu-10Ni合金的强度及塑性均大幅度提高;在准静态拉伸加载条件下,与65W-35Cu合金相比,65W-25Cu-10Ni合金的强度较高,塑性没有明显提高。机理分析表明,与65W-35Cu合金相比,65W-25Cu-10Ni合金中W-W连接度较低,粘结相由Cu相转变为Cu0.81Ni0.19固溶体,且W与粘结相之间形成了冶金结合,以上3个因素共同导致65W-25Cu-10Ni合金强度的提高;此外,W-W连接度的降低以及W-粘结相界面结合强度的提高是65W-25Cu-10Ni合金在准静态压缩加载条件下塑性提高的原因。

W particles were coated with Ni using an electroless plating technique, and the Ni coated W powders were mixed uniformly with copper powders. 65W-25Cu-10 Ni alloy with low W-W contiguity was prepared by a SPS method using the composite powders, and the quasistatic mechanical properties were studied. The results show that after the Ni electroless plating process, Ni uniformly distributes on the surface of W particles, and the interface bonding is well. The 65W-25Cu-10 Ni alloy prepared by SPS is uniform and dense in microstructure. Compared with 65W-35 Cu alloy, 65W-25Cu-10 Ni alloy exhibits higher strength and better ductility under quasistatic compression condition, while it presents higher strength under quasistatic tensile condition, but the ductility is not obviously improved. The analysis of the failure mechanism shows that compared with 65W-35 Cu alloy, W-W contiguity evidently decreases in the 65W-25Cu-10 Ni alloy, the matrix is replaced by Cu0.81Ni0.19 solid solution, and metallurgical bonding is formed between W and the matrix. All these above factors are beneficial to increase the strength of 65W-25Cu-10 Ni alloy. Meanwhile, the decrease of W-W contiguity and the increase of the interfacial strength account for the ductility increase of 65W-25Cu-10 Ni alloy under quasistatic compression condition.