Y_2O_3弥散强化铜基复合材料的强化机制

Strengthening Mechanisms of Y_2O_3 Dispersion Strengthened Copper-based Composites

通过力学性能测试和TEM观察,对液相原位反应法制备的Cu-0.9Y2O3(体积分数,%)复合材料的凝固机理和强化机制进行研究。结果表明:在液相线温度上,熔融的Cu-Y合金在等温凝固的条件下,原位生成的纳米级Y2O3粒子均匀弥散分布在铜基体上,并没有在晶界附近聚集长大;通过不同强化机制定量计算Cu-0.9Y2O3复合材料的抗拉强度为593 MPa,与实测值568 MPa相当,其中,Orowan机制和切割机制作为主要的强化机制是共同存在的,其产生的强度增值分别为174和207 MPa,晶界强化作为辅助强化机制对材料的强度也有贡献。

Mechanical test and TEM observation on Cu-0.9Y2O3（volume fraction, %） composites prepared by insitu reaction at liquidus temperature were conducted to research the solidification and strengthening mechanism. The results show that yttrium atoms are in-situ oxidized into nanoscale yttria at liquidus-temperature. Y2O3 nano-particles are uniformly distributed in copper matrix, rather than agglomerating at grain boundaries. Quantitative contributions were calculated for different strengthening mechanisms by extant strengthening theories. For the Cu-0.9Y2O3 composites, the calculated strength is 593 MPa, which is in a good agreement with the experimental value（568 MPa）. The dominant strengthening mechanisms are Orowan and shearing mechanism with their contributions are174 and 207 MPa, respectively. The strength contribution due to grain-boundary strengthening which as auxiliary strengthening mechanism is 12 MPa.