挤压铸造Mullitef/M124F复合材料性能分析

用挤压铸造工艺制备了莫来石短纤维(Mullitef)增强马勒124合金(M124F)铝基复合材料,研究了该复合材料从室温到400 ℃高温的拉伸性能及热膨胀性能.试验结果表明,体积分数为17%的Mullitef增强复合材料的300 ℃高温极限抗拉强度为228 MPa,比其他短纤维或晶须增强相铝基复合材料提高15%以上;热膨胀系数(CTF)为16.5×10-6 K.通过对3种试样的拉伸行为及SEM断口观察,分析了复合材料的静载破断机制,表明裂纹源主要生成于增强纤维与基体的复合界面上.     

液固挤压SiCp/LY12复合材料的组织与性能

探讨了液固挤压SiCp/LY12复合材料的组织与性能特征及其相互之间的关系. 研究表明, 其基体组织晶粒细小, SiC颗粒基本呈均匀随机分布, 无明显堆积及脱粘现象, 且与基体结合良好; 抗拉强度比基体材料提高20%～32%. 从而为颗粒增强金属基复合材料管、棒材的制备提供了一种减少工序、节能节材的可行方法.     

液-固挤压复合材料系统的模糊神经网络建模

针对液-固挤压复合材料管、棒材成形时工艺参数难于选取、试验工作量大的问题,在正交试验的基础上,结合有限元模拟数据,构建200组样本集,将其中的150组作为训练样本用于网络的训练学习,其余的50组作为测试样本用于验证网络的精确性.通过对补偿模糊神经网络学习算法实现中的关键技术问题的处理,如输入、输出变量模糊集的划分、模糊规则的提取、学习速率的确定等,基于模糊神经网络建立了液-固挤压复合材料工艺系统模型,得到了浸渗时间与其它关键参数之间的映射关系及模糊规则,利用该模型,对关键工艺参数进行预测,预测值与试验值吻合较好.这为该工艺的实际应用和过程控制奠定了基础.     

液-固挤压复合材料管材成形过程中温度场的有限元分析

建立了液－固挤压复合材料管材成形过程的非稳态温度场的有限元数学模型。开发了相应的模拟软件。对复合材料管材成形过程的温度场进行了模拟研究。得到了成形全过程的温度场分布图。依据该图可以预测管材成形质量。结合实验分析了影响管材成形质量的内在原因。模拟结果与实验结果吻合较好。为深入了解金属的流动规律和合理选择工艺参数奠定了理论基础。     

挤压铸造SiC_p/LY12复合材料的组织与性能

探讨了挤压铸造SiCp/LY12复合材料的组织与性能特征及其相互之间的关系。研究表明,其基体组织晶粒细小, SiC颗粒基本呈均匀随机分布,无明显堆积及脱粘现象,且与基体结合良好。抗拉强度和弹性模量比基体材料分别提高 20％～32％和7.6％～43％,从而为颗粒增强金属基复合材料管、棒材的制备提供了一种减少工序,节能节材的可行方法。     

挤压铸造SiC_p/ZL111铝基复合材料

研究了含量为20%的SiC颗粒增强ZL111铝基复合材料锭重熔后,挤压铸造件的组织和性能。结果表明,可以采用卧式挤压铸造方法制备铝基复合材料铸件,浇注温度为710℃,挤压冲头速度为0.4m/s,比压为135MPa;组织内SiC颗粒分布仍然保持分散,没有发生团聚,铸件不同部位SiC含量基本一致;但是SiC颗粒只分布在共晶组织内;铸件耐磨性显著提高,导致切削加工刀具磨损急剧增加,但布氏硬度(HB)为76.7～94.4,与ZL111铝合金相差不多。     

挤压铸造条件下铝基复合材料铸造流动性研究

研究SiCp/A356铝基复合材料在铸造压力、碳化硅含量、金属模温和铸件尺寸厚度(代表凝固冷却速率)等不同工艺参数下的铸造流动性.结果表明,随着SiC颗粒添加量的增加,铝基复合材料的流动性呈现降低的趋势.而随着铸造压力的升高,复合材料的流动性呈现显著增加的情况.但当压力超过10 MPa以上时,其流动性并未有显著增加,仅是微幅增加而已.其次,增加模具的温度也可以增加铝基复合材料的流动性,尤其对薄件(厚2 mm)更为明显.     

挤压铸造条件下铝基复合材料铸造流动性研究

研究了SiCp/A356铝基复合材料在不同铸造压力、碳化硅含量、金属型温和铸件尺寸厚度(代表凝固冷却速率)等工艺参数下的铸造流动性.结果显示,随着SiC颗粒添加量的增加,铝基复合材料的流动性呈显著降低的趋势.随着铸造压力的提升,复合材料的流动性显著增加.但当压力超过10MPa后,流动性仅是微幅增加.其次,提高模具温度也可以增加铝基复合材料的流动性,尤其对壁厚2mm左右的件更为明显.     

液-固挤压复合材料过程模具传热特性研究

采用理论分析与试验研究相结合的方法,研究了液固挤压复合材料工艺过程的模具温度场,得到了模具温度沿径向和纵向随时间变化的曲线,分析了模具温度变化规律及其对成形过程的影响,模拟结果与试验结果吻合较好,说明所建模型的有效性,为优化模具设计和液-固挤压复合材料工艺的实际应用奠定了基础.     

液固两相区等温热处理对ZA101枝晶形貌的影响

本文研究了液固两相区等温热处理对合金ZA101枝晶形貌的影响。试验分析了不同加热温度、保温时间和加热速度对其枝晶组织的影响。结果表明，经等温处理的ZA101合金组织形态将由枝晶向非枝晶转变，并最终生产成本为适合半固态加工的细小近球状初生相组织；加热速度的增加有助于提高其初生相组织的圆整度。     

CuO／Al自生复合材料的反应动力学

本文探讨了一种Ａｌ２Ｏ３粒子增强低温反应合成自生铝基复合材料的制备工艺。用热分析和电镜研究了材料的显微组织．     

挤压加工对SiCp／Al复合材料组织和性能的影响

开展了挤压加工对 Si Cp/ Al复合材料显微组织和力学性能的实验研究。结果表明 :挤压加工有助于提高 Si C颗粒分布的均匀性 ,挤压棒料中的 Si C颗粒在挤压方向上定向、有序地排列 ,呈现出带状组织的特征 ;挤压加工还可以消除 Si Cp/ Al复合材料毛坯中的显微疏松缺陷 ,改善铝合金基体对 Si C颗粒损伤的容限性能 ,从而大幅度地提高复合材料的强度和塑性     

铝电磁铸轧液固区中流体行为

介绍了铝电磁连续铸轧液固相区中电磁场的基本特性,分析了流体的运动轨迹与两种不同液固相界的耦合形式,探讨了它们对液固相边界层的作用效果,描述了正弦波振动对液固相界面稳定性的影响。     

SiC_p/ZL201复合材料的力学性能

研究了ＳｉＣｐ尺寸、含量及热处理工艺对铸造ＳｉＣｐ／ＺＬ２０１复合材料的室温和高温力学性能的影响。随ＳｉＣｐ含量的提高和粒子尺寸的增大,复合材料的室温抗拉强度呈下降趋势。随温度升高,基体合金的抗拉强度急剧下降,而复合材料的则下降较小。当温度大于２４０℃时复合材料的抗拉强度高于基体合金,表明ＳｉＣｐ的加入显著提高了基体合金的高温抗拉强度。     

STUDY ON DIFFUSION WELDING OF ALUMINIUN MATRIX COMPOSITE

1.IntroductionAluminummatrixcomposite,thankstoitsexcellentcomprehensivepropertiessuchashighspecificstrength,highspecificmodule,resistancetoelevatedtemperature,resistancetoradiationandgooddimensionalstability,hasattractedgreatattentionfIDmmaterialscientistsbothhomeandaboard.Asoneofsubstitutesofconventionalmetals,alundniummatrixcompositeshavebeenwidelyaPPliedinthefieldsofaerospace,aviationandautomobile~lufacturingindustries,andbecomesmainsubjectinresearchanddevelopmentofmetalmatrixcomPOsites.A…     

铜/钢复合板焊接工艺

通过对铜／钢复合板接头焊接性的分析，制定了适于铜／钢复合板的焊接工艺。在试件焊接性试验和多次接头返修试验后，试件经无损检验及力学性能试验，接头性能完全满足使用要求。     

RECIPROCATING EXTRUSION OF IN SITU Mg_2Si REINFORCED Mg-Al BASED COMPOSITE

M92Si reinforced Mg-Al based composite with high amount o/silicon was prepared by permanent mould casting, and then extruded by reciprocating extrusion （RE） after the composite was processed by homogenization heat treatment. The effect of RE processing on the morphology and size of M92Si and the mechanical properties of the com- posite were investigated, to develop new ways to refine the M928i phase and improve its shape. The result showed that RE was very useful in refining the M92Si phase. The more the RE processing passes, the better the refining effect would be. Moreover, the uniform distribution of M928i phases would be more in the composite. After the composite was processed by RE for 12 passes, most M92Si phases were equiaxed, with granular diameter below 20 μm, and distributed uniformly in the matrix of the composite. The mechanical properties of the composite could be increased prominently by RE processing, and were much higher than that in the as-cast state. As the temperature rises, the tensile strength is reduced. For the composite RE processed for 12 passes, the tensile strength, yield strength, and elongation are 325.9 MPa, 211.4 MPa, and 3.3% at room temperature, whereas, 288.2 MPa, ,207.7 MPa, and 7.8%, respectively, at 150℃. In comparison with the properties at room temperature, the tensile strength and yield strength are high and only decrease by 11.6% and 1.8% at 150℃. The M928i reinforced Mg-Al based composite possesses good heat resistance at 150℃. The excellent resistance to effect of heat is attributed to the high melting tempera- ture and good thermal stability of fine Mg2Si phases, which are distributed uniformly in the composite, and effectively hinder the grain boundary gliding and dislocation movement.     

RECIPROCATING EXTRUSION OF IN SITU Mg2Si REINFORCED Mg-A1 BASED COMPOSITE

Mg2Si reinforced Mg-Al based composite with high amount of silicon was prepared by permanent mould casting, and then extruded by reciprocating extension (RE) after the composite was processed by homogenization heat treatment. The effect of RE processing on the morphology and size of Mg2Si and the mechanical properties of the composite were investigated, to develop new ways to refine the Mg2Si phase and improve its shape. The result showed that RE was very useful in refining the Mg2Si phase.The more the RE processing passes, the better the refining effect would be. Moreover,the uniform distribution of Mg2Si phases would be more in the composite. After the composite was processed by RE for 12 passes, most Mg2Si phases were equiaxed, with granular diameter below 20 μm, and distributed uniformly in the matrix of the composite. The mechanical properties of the composite could be increased prominently by RE processing, and were much higher than that in the as-cast state. As the temperature rises, the tensile strength is reduced. For the composite RE processed for 12 passes, the tensile strength, yield strength, and elongation are 325.9 MPa, 211.4 MPa,and 3.3% at room temperature, whereas, 288.2 MPa, 207.7 MPa, and 7.8%, respectively, at 150° C. In comparison with the properties at room temperature, the tensile strength and yield strength are high and only decrease by 11.6% and 1.8% at 150°C. The Mg2Si reinforced Mg-Al based composite possesses good heat resistance at 150° C. The excellent resistance to effect of heat is attributed to the high melting temperature and good thermal stability of fine Mg2Si phases, which are distributed uniformly in the composite, and effectively hinder the grain boundary gliding and dislocation movement.     

粉末冶金制备SiC_P/2009Al复合材料的相组成和元素分布

采用粉末冶金法制备SiCp/2009AI复合材料热压锭,并对热压锭进行了热挤压,分析了热压态和挤压态复合材料的相组成和元素分布.结果表明:热压锭存在轻微的元素偏析,下部Cu和Mg含量略高于上部.热压态复合材料组成相主要为Al,SiC,Al2Cu和Mg2Si,另外还含有少量的Al7Cu2Fe和Mg的氧化物.经固溶处理后,Al₂Cu和Mg₂Si溶解,Cu在基体中均匀分布,但Mg仍偏聚于原始铝颗粒边界和SiC团聚处.挤压变形不改变复合材料的相组成,但使SiC分布更均匀并破碎了铝颗粒表面的氧化膜.挤压态复合材料经固溶处理后,Cu和Mg均在基体中均实现了均匀分布.     

EFFECT OF OVERLAPPING TREATMENT ON MICROSTRUCTURE OF LASER CLAD WC/Ni60A COMPOSITE COATING

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