真空雾化Cu-Cr合金组织与性能分析

发布时间：2018-06-12 21:54

  本文选题：真空雾化 + Cu-Cr(Fe)合金　； 参考：《西安理工大学》2017年硕士论文

【摘要】：本课题使真空雾化的Cu-Cr合金粉末作为制备Cu-Cr合金的基本粉末,通过热压烧结获得Cu-Cr合金材料,可大幅度降低合金中Cr的尺寸,从而提高Cu-Cr合金的综合性能。研究了不同雾化工艺、雾化参数下合金粉末的粒径分布及表面形貌,确定了制备Cu-Cr合金粉末的最佳工艺及参数:并分析了 Cr含量的提高对Cu-Cr合金粉末组织和性能的影响及不同冷速合金中Cr的形貌变化规律:研究了不同成分Cu-Cr合金烧结样及时效处理后的组织与性能的变化;探究第三组元Fe的加入对合金组织与性能的影响。所得实验结果如下;(1)真空雾化制备的Cu-Cr合金粉末具有更高的球形度,粉末基本为规则的球形颗粒,含有极少量的异形粉,且粉末的氧含量极低。制备Cu-Cr合金粉末的最佳的雾化参数为:雾化漏嘴粒4mm、雾化压力5MPa、过热度150℃。在该雾化参数下获得粉末的细粉收得率高、粉末粒径分布范围窄、粉末为规则的球形颗粒。(2)随着合金中Cr含量的提高, Cu-Cr合金粉末组织中的初生Cr相逐渐增多,初生Cr相尺寸维持在11μm。在本实验条件下,真空雾化法将Cu-Cr合金粉末中Cr的固溶度提高至3.26wt%。随冷速的提高,Cu-Cr合金中Cr的形貌由长度约为5μm的棒条状向球形颗粒转变。当冷速达到1O5K/s时,Cr完全固溶进Cu基体中形成Cu-Cr共晶组织。(3)不同成分Cu-Cr合金粉末热压烧结后,合金的致密度随Cr含量的提高呈下降趋势。当Cu-Cr合金中的Cr含量超过2.5wt%时,在基体中出现了球状的初生Cr相并随Cr含量的增加而增多,初生Cr相的尺寸约为1μm,比常规铸造法制备的Cu-Cr中Cr的尺寸缩小10倍左右。(4) Cu-Cr合金烧结样品的导电率随Cr含量的增加而降低,硬度随Cr含量增加而升高。合金中的Cr含量从2.5wt%增加到4wt%时,导电率从86.5%IACS降低到73.4% IACS,硬度从61,5HB增加73.2HB。合金成分为Cu-3Cr时,使用热压烧结法比常规铸造法所合金的硬度提高了 13HB,导电率提高了29.2%IACS Cu-4Cr合金在500℃时效2h后综合性能最优,硬度增加到82HB,导电率提高至77.8%IACS。(5)Cu-Cr合金中加入第三组元Fe降低了Cr在Cu中的固溶度,使Cu-2.5Cr-0.5Fe合金粉末组织中出现了少量的初生Cr相,同时大量的Cr沿晶界析出。相比Cu-3Cr合金,Cu-2.5Cr-0.5Fe合金烧结样硬度提高到78.2HB,导电率下降至65.4%IACS。
[Abstract]:In this paper, the vacuum atomized Cu-Cr alloy powder is used as the basic powder for the preparation of Cu-Cr alloy. The Cu-Cr alloy material can be obtained by hot pressing sintering, which can greatly reduce the size of Cr in the alloy and improve the comprehensive properties of the Cu-Cr alloy. The particle size distribution and surface morphology of alloy powder under different atomization process and atomization parameters were studied. The optimum process and parameters for preparing Cu-Cr alloy powder were determined. The effect of Cr content on the microstructure and properties of Cu-Cr alloy powder and the variation rule of Cr morphology in different cold speed alloy were analyzed. Changes of microstructure and properties of gold sintered samples and aging treatment; The effect of the addition of the third element Fe on the microstructure and properties of the alloy was investigated. The experimental results are as follows: (1) the Cu-Cr alloy powder prepared by vacuum atomization has a higher spherical degree, the powder is basically a regular spherical particle, contains a very small amount of special-shaped powder, and the oxygen content of the powder is very low. The optimum atomization parameters for the preparation of Cu-Cr alloy powder are as follows: atomizing leakage particle 4mm, atomizing pressure 5MPa, superheat degree 150 鈩，

本文编号：2011214