Fe基非晶颗粒增强铝基复合材料

【作者】 张帆；

【导师】 蒋业华；

【作者基本信息】 昆明理工大学 ， 材料加工工程， 2019， 硕士

【摘要】 随着新时代的不断进步,科学技术也随之得到很大的提升。为了紧随时代的更新,材料领域也不断加快进程,新型高强轻质材料应运而生。铝基复合材料具有高强度和低密度等优异的性能,很符合现在对新型材料的需求,所以铝基复合材料称为当今应用领域研究的重点对象。本课题通过XRD、DSC、SEM、EDS等表征手段对通过球磨和放电等离子烧结所制备出的Fe基非晶增强铝基复合材料进行表征,并进行力学性能测试,确定其相应增强机理及其影响因素。(1)利用XRD确定球磨后不同体积增强比的Fe基非晶增强铝基复合材料粉末中非晶增强相并未发生晶化现象。利用DSC确定不同体积增强比的Fe基非晶增强铝基复合材料的烧结温度分别为400℃、450℃、500℃、550℃。其中400℃和450℃、500℃处于非晶玻璃化转变温度以下;550℃处于过冷液相区。利用SEM确定其增强相的分布,以确定是否发生团聚现象,并观察其界面结合性。利用EDS确定其是否发生第二相增强,以及元素分布情况。(2)当增强比相同时,Fe基非晶增强铝基复合材料的烧结温度越高,试样致密度越好,且在500℃时致密度达到97.6%;当复合材料体积分数为10%时,复合材料组织结构缺陷较少,致密度较高。(3)对压缩实验结果分析发现相同体积增强比的Fe基非晶增强铝基复合材料其压缩屈服强度和弹性模量在500℃以下随温度提高有升高的趋势,压缩屈服强度和弹性模量在体积比40%烧结温度550℃达到峰值的396MPa和104.81GPa,但是在应变10%就发生断裂现象,塑性严重下降。(4)对于相同烧结温度Fe基非晶增强铝基复合材料除烧结温度在550℃以外,其压缩屈服强度和弹性模量在增强比10vol.%以上随着增强比提高其压缩屈服强度和弹性模量逐渐降低,在10vol.%达到峰值。(5)进行压缩实验确定其烧结温度为500℃,体积分数为10vol.%Fe基非晶增强铝基复合材料相比其他烧结温度和体积增强比材料具有较高的压缩屈服强度276MPa和弹性模量78.17GPa,并同时具有很好地塑性。通过对样品的SEM和EDS图谱并对应其力学性能进行分析得知:其增强机理为颗粒增强、位错增强、细晶强化和元素扩散形成第二相的混合增强机制。(6)有限元模拟时,析出相厚度越大的Fe基非晶增强铝基复合材料的力学性能越好。分析结果可能是析出相在界面形成第二相增强效应,进而增强了复合材料的压缩屈服强度和弹性模量。在增强相较少时,由于增强相含量不足以承担更多的形变量,Al基体主要承担形变,所以导致力学性能较差。在增强相较多时,增强相之间会相互影响,使应力集中,进而影响到力学性能。所以当增强比为10%时,基体所受应力最小,应力集中区域最少,弹性模量最大,Al基复合材料的力学性能最佳。更多还原

【Abstract】 The new era is constantly improving,technology have also been greatly improved.In order to keep up to date,the field of materials is also accelerating,and new high-strength lightweight materials have emerged.aluminum matrix composites have excellent properties such as high strength and low density,which is in line with the demand for new materials.Therefore,aluminum-based composite materials are called the focus of research in today’s application fields.In this paper,the Fe-based amorphous reinforced aluminum matrix composites prepared by mechanical alloying and spark plasma sintering were characterized by XRD,DSC,SEM,EDS and other characterization methods,and the mechanical properties were tested to determine their corresponding enhancement mechanism and its influence.factor.(1)The amorphous phase of Fe-based amorphous reinforced aluminum matrix composite powder with different volume enhancement ratio after ball milling was determined by XRD.The sintering temperatures of Fe-based amorphous reinforced aluminum matrix composites with different volume enhancement ratios determined by DSC were 400℃,450℃,500℃,and 550℃,respectively.Among them,400℃ and 450℃,500℃ is below the amorphous glass transition temperature;550℃ is in the supercooled liquid region.The distribution of the reinforcing phase was determined by SEM to determine whether agglomeration occurred and the interfacial bonding was observed.EDS is used to determine if a second phase enhancement occurs and the element distribution.(2)When the reinforcement ratio is the same,the higher the sintering temperature of the Fe-based amorphous reinforced aluminum matrix composite,the better the density of the sample,and the density reaches 97.6% at 500℃;when the composite volume fraction is 10%.At the time,the composite structure has fewer structural defects and high density.(3)Analysis of the results of compression experiments found that the yield strength and elastic modulus of Fe-based amorphous reinforced aluminum matrix composites with the same volume-enhanced ratio increase below 500℃ with increasing temperature,and the yield strength and elastic modulus are The volume ratio of 40% of the sintering temperature of 550℃ reached a peak of 396 MPa and 104.81 GPa,but the fracture phenomenon occurred at 10% strain,and the plasticity was seriously degraded.(4)For the Fe-based amorphous reinforced aluminum matrix composites with the samesintering temperature,except for the sintering temperature of 550℃,the yield strength and elastic modulus increase the yield strength and elastic modulus with the enhancement ratio above 10 vol.%.The amount gradually decreased and peaked at 10 vol.%.(5)The compression test was carried out to determine the sintering temperature of 500℃,the volume fraction of 10 vol.% Fe-based amorphous reinforced aluminum matrix composite material has higher yield strength 276 MPa and elastic modulus than other sintering temperature and volume enhancement ratio materials.The amount is 78.17 GPa and at the same time has good plasticity.By analyzing the SEM and EDS spectra of the samples and corresponding to their mechanical properties,the enhancement mechanism is the mixing enhancement mechanism of particle reinforcement,dislocation enhancement,fine grain strengthening and element diffusion to form the second phase.(6)In the finite element simulation,the mechanical properties of Fe-based amorphous reinforced aluminum matrix composites with larger thickness of precipitated phase are better.The analysis result may be that the precipitation phase forms a second phase enhancement effect at the interface,thereby enhancing the yield strength and elastic modulus of the composite.When the reinforcing phase is small,since the content of the reinforcing phase is insufficient to bear more deformation variables,the Al matrix mainly bears deformation,so that the mechanical properties are poor.When the reinforcing phase is more,the reinforcing phases interact with each other to concentrate the stress,which in turn affects the mechanical properties.Therefore,when the reinforcement ratio is 10%,the matrix is subjected to the least stress,the stress concentration region is the least,the elastic modulus is the largest,and the mechanical properties of the Al-based composite material are the best.更多还原