土粉体对铝铜合金的影响.pdf

摘 要 随着工业技术的发展和社会的进步，铝的应用范围逐渐扩大，对铝合金性能的要求 也随之越来越高。研究发现，铸态组织细小均匀的铝合金具有良好的强度及塑韧性。所 以，细化晶粒对铝合金发展的重要性不言而喻。铸态组织的微细化处理已成为一种专门 技术，通过稀土与铝合金液体中的元素产生相互作用，改变析出相和共晶产物的形态和 分布，达到细化晶粒的目的从而改变铸态力学性能。 本文通过向铸造铝铜合金中加入不同量的改性稀土粉体，对加入量为0%、0.1%、 0.3%和0.5%的试样分别进行金相组织观察、拉伸试验和硬度测试。研究结果表明：加 入稀土粉体后显著改变Al-Cu合金的微观组织，原α-Al晶界处分布的共晶相网络被打断， 呈不完全连续网状，而且稀土粉体对Al-Cu合金具有明显的变质效果，促使枝晶细化； 铸造铝铜合金的抗拉强度和延伸率 得到了一定的提高，当稀土粉体加入量为0.1%时， 抗拉强度由原始值154.7MPa增加到176.5MPa，提高了14%，延伸率由1.0%提高到了 1.66%，提高了66%,稀土粉体还可以提高铸造铝铜合金的布氏硬度值，其中当稀土粉体 加入量为0.3%时硬度值提高最显著，布氏硬度(HB)由68提高到了85，提高了25%。 关键词： 稀土粉体 铸造铝铜合金 力学性能 显微组织 ABSTRACT Withtheadvancementofindustrialtechnologyandsociety,thescopeofapplication ofaluminumgraduallyexpandaluminumalloyperformancerequirementsalsowillbegetting higher and higher. The study found that even small organizations cast aluminum alloy has good strengthandplasticity andtoughness.Therefore,the importance ofgrainrefinement of aluminumdeveloping is self-evident.Fineprocessing of ingotmicro structurehas become a special technique.Adding rare earth and alloy elements in a liquid to produce interaction, change of precipitation phase and the morphology and distribution of eutectic product , achievethepurposeoffinegrainstoalteras-castmechanicalproperties. This paper is about adding different amounts of modified powders, and complete the micro structure observation, hardness test and tensile test of the samples of no powder,the powder amount of 0.1%,the powder amount of 0.3% and the powder amount of 0.5%.The results show that:when the powder is added，there is a significant change ofAl-Cu alloy micro-structure,thedistributionofeutecticphase atgrainboundaryisinterrupted,continuous network is incomplete, and it has a obvious effect of Al-Cu alloy of metamorphism, prompting dendrite refining.The tensile strength of castingAl-Cu alloy and elongation rate have been increased,when the adding amount is 0.1%,t