半固态ZA27合金电磁搅拌工艺及其组织和性能的研究

采用电磁搅拌装置制备ZA27合金半固态浆料，研究不同搅拌参数对非枝晶组织和性能的影响。结果表明：搅拌电流越大，晶粒越细小致密，搅拌时间短不足以打碎、圆整ZA27凝同时的先结晶组织，搅拌时间长，先结晶相易发生聚集长大，导致力学性能下降。搅拌时间10min左右，ZA27合金的组织和性能较佳。     

铸造锌铝合金ZA27变质处理的研究现状与展望

介绍了变质元素对铸造锌铝合金ZA27显微组织与性能的影响,分析了变质机理,并对ZA27合金变质处理的发展趋势作了展望。     

ZA27合金的铸态组织及晶界共晶体

研究分析了ZA27合金(锌-铝合金)的铸态组织及其分布特点。电子探针分析表明ZA27     

稀土Ce对ZA27合金组织和力学性能的影响

在ZA27合金中加入稀土元素Ce,并采用挤压铸造的加工方法，寻求细化组织和提高力学性能的途径.稀土Ce使ZA27合金的晶粒细化，β相和ε相分布更均匀，并且在晶界处生成了不规则的化合物，该化合物包含Zn、Al、Cu、Ce、Mg等元素.随着含Ce量的增加，化合物的数量增多，有少量偏聚成大块.在挤压力作用下，晶界处ε相要少些.添加稀土Ce后，挤压铸造ZA27合金的抗拉强度、伸长率、硬度均有所提高.结果表明，含Ce量为0.15%时挤压铸造ZA27合金组织和力学性能最好.     

电磁搅拌对Al-18Mg2Si合金组织与性能的影响

为了研究电磁搅拌对Al-18Mg₂Si合金组织及性能的影响规律,对Al-18Mg₂Si合金进行了不同磁感应强度和搅拌时间的电磁搅拌实验.通过显微组织分析和力学测试表明,提高磁感应强度和延长搅拌时间,合金中的初生Mg₂Si相明显圆整、细化;合金的抗拉强度和硬度也有一定程度的提高.但磁感应强度过大,会导致合金组织粗化;搅拌时间过长,会使性能降低.磁感应强度在0.01～0.012T、时间持续60s的电磁搅拌能够显著改善Al-18Mg₂Si合金的显微组织和力学性能.     

ZA52-xY合金相图计算及在合金设计中的应用

以相图热力学计算为基础,计算了ZA52-xY镁合金的垂直截面图,设计了三种ZA52-xY镁合金(Y的质量百分含量分别为0%,0.5%和1.0%).采用光学显微镜、扫描电镜以及微机控制电子万能试验机,对添加不同Y含量的ZA52镁合金进行了显微组织观察和室温拉伸性能测试.结果表明,随着Y元素的加入,ZA52合金的晶粒组织细化,合金的抗拉强度和延伸率都得到提高.固溶时效处理的ZA52-xY合金的显微组织由α-Mg,Al2Y,Al3YMg17Al12和MgZn2组成.当ZA52合金中加入0.5%Y时,合金的抗拉强度达到251 MPa.     

挤压铸造ZA27合金的力学性能及摩擦磨损性能

研究了挤压铸造对ZA27合金力学性能的影响,挤压铸造可以显著地提高ZA27合金的常温力学性能和高温力学性能.随着比压的增加,其综合力学性能提高.比压为750 MPa时,与金属型重力铸造合金相比,抗拉强度提高了约19.2%,硬度提高了约25.5%,伸长率增加了12.3%.采用MM-W1立式万能摩擦磨损试验机研究了比压对ZA27合金的摩擦磨损性能的影响,结果表明,在转速为200 r/min,载荷为100 N,摩擦副为45钢,20号机油润滑条件下,挤压比压为750 MPa时,合金的摩擦磨损性能较好.     

轧制工艺对ZA35合金组织和性能的影响

为了提高ZA35合金的力学性能,采用轧制工艺制备ZA35合金板坯,利用x-射线衍射仪(XRD)、金相显微镜(OE)、扫描电子显微镜(SEM)以及能谱分析(EDS)等技术分析和检测了ZA35合金铸态、不同轧制态和热处理态的显微组织和性能.结果表明:轧制可以显著提高ZA35合金的综合力学性能,使抗拉强度提高了27.8%,硬度指标提高了36.4%,伸长率比铸态增加了近2倍.轧制使合金组织细化,初生α相增多,ε相由块状变成细小的点状弥散分布于枝晶间.轧制合金在经过365℃固溶3h和120℃时效12h热处理后合金力学性能最好,抗拉强度达到512MPa、伸长率为4.9%、硬度为HB127.     

原位自生Sip/ZA40复合材料的组织及性能研究

采用原位自生铸造法制备了ZA40-1.5wt%Si、ZA40-3.0wt%Si、ZA40-4.5wt%Si和ZA40-6.0wt%Si合金,获得了Si颗粒分布均匀、尺寸细小、形貌规则的锌基复合材料。分析了复合材料的组织形貌,检测了复合材料的硬度和冲击性能。研究结果表明：高铝锌合金加入硅后,随着硅含量的增多,Si除了在组织中形成共晶硅相外,还析出初晶硅;随着硅含量的增加初晶硅相数量增多,合金的硬度提高,冲击韧性下降。     

ZA27合金中Y及Fe的晶界偏聚电子理论研究

根据分子动力学理论建立了液态ZA27合金的原子集团，结合计算机编程构造出ZA27合金α相与液相共存时的原子构形及α相大角度重位点阵晶界模型.利用递归法计算了Fe、Y固溶于晶粒内，游离于固液相界面及其在α相晶界处的环境敏感镶嵌能.由此得出：Fe、Y处于固液相界区时比在晶内更稳定，并解释了Fe、Y在α相内溶解度很小，结晶时富集于固液相界前沿液体中，从而导致凝固结束后Fe、Y偏聚于晶界，形成成分复杂的稀土化合物的事实.     

Effect of Nano-sized B_4C Addition on the Mechanical Properties of ZA27 Composites

In order to understand the influence of nano-sized B_4C additive on ZA27 alloy, mechanical and physical properties of ZA27-B_4C nanocomposites were investigated in terms of B_4C content. While physical properties were determined in terms of microstructural studies, density and porosity tests, mechanical properties were determined in terms of ultimate tensile strength(UTS) and hardness experiments. Morphological and microstructural studies were carried out with scanning electron microscopy(SEM). The experimental results indicate that nano-sized B_4C can be used to enhance the mechanical properties of ZA27 alloy effectively. The highest mechanical performance can be obtained at ZA27-0.5% B_4C(in weight) nanocomposite with values of tensile strength(247 MPa) and hardness(141,18 BH) and low partial porosity(0.5%). After a pick point, increasing B_4C ratio may cause the formation of agglomeration in grain boundaries, that's why density, tensile strength, and hardness values are declined.     

Effect of nano-sized B<Subscript>4</Subscript>C addition on the mechanical properties of ZA27 composites

In order to understand the influence of nano-sized B₄C additive on ZA27 alloy, mechanical and physical properties of ZA27-B₄C nanocomposites were investigated in terms of B₄C content. While physical properties were determined in terms of microstructural studies, density and porosity tests, mechanical properties were determined in terms of ultimate tensile strength (UTS) and hardness experiments. Morphological and microstructural studies were carried out with scanning electron microscopy (SEM). The experimental results indicate that nano-sized B₄C can be used to enhance the mechanical properties of ZA27 alloy effectively. The highest mechanical performance can be obtained at ZA27-0.5% B₄C (in weight) nanocomposite with values of tensile strength (247 MPa) and hardness (141,18 BH) and low partial porosity (0.5%). After a pick point, increasing B₄C ratio may cause the formation of agglomeration in grain boundaries, that’s why density, tensile strength, and hardness values are declined.     

化学成分对锌基合金性能的影响

研究了成分对锌基合金性能的影响,结果表明,ＺＡ－４０合金具有最佳的组织和性能,在锌基合金中起提高耐磨性作用的硬质点为ＣｕＺｎ４。     

As-cast microstructure,mechanical properties and casting fluidity of ZA84 magnesium alloy containing TiC

The as-cast microstructure, mechanical properties and casting fluidity of ZA84 alloy containing TiC were investigated. The experimental results indicate that adding 0.5wt%TiC to ZA84 alloy can refine the as-cast microstructure, and do not cause the formation of any new phase. After 0.5wt%TiC was added to the ZA84 alloy, the morphology of ternary phases on the grain boundaries changed from coarse quasi-continuous net to fine disconnected net, and the distribution of ternary phases became dispersive and homogeneous. At the same time, the tensile properties of ZA84＋0.5TiC alloy at room temperature were comparable to those of AZ91D alloy, and were higher than those of ZA84 alloy. At 150 ℃, the tensile and creep properties of ZA84＋0.5TiC alloy were also higher than those of ZA84 and AZ91D alloys. In addition, compared with the AZ91D alloy, the casting fluidity of ZA84＋0.5TiC alloy was slightly poor, but better than that of ZA84 alloy. The reason could be related to the effect of TiC on the solidification temperature range of ZA84 alloy.     

ZA27合金在循环应力作用下的疲劳特性

研究了ＺＡ２７ 合金在室温下的低周疲劳性能, 得到两种处理状态下ＺＡ２７ 合金在恒应变幅下的循环应力—应变曲线, 并对两种状态下合金的显微组织及疲劳试件断口进行了显微分析． 结果表明： ＺＡ２７ 合金在铸态下表现为循环软化, 其原因与铸态组织晶粒的不均匀性以及内应力在循环应力作用下的衰减等有关; 热处理合金表现为循环硬化, 是由于热处理显微组织中沉淀相弥散、均匀、稳定地分布于基体中, 造成位错运动的障碍以及不断开动的位错源造成晶粒内位错密度迅速增加起到了循环硬化的作用．     

硅、稀土元素对 ZA27 力学性能影响规律的研究

采用正交组合回归设计试验方法，研究了硅、稀土元素对ＺＡ２７合金力学性能的影响规律。研究结果表明，硅、稀土元素对合金的抗压强度、冲击韧性产生显著影响，且对综合力学性能的影响存在最佳配比。     

Microstructure Evolution of Semi-solid Processed Hyper-eutectic Al-30%Si Alloy

Semi-solidmetalformingtechnologyhasachievedgreatprogressinthepasttenyearsbecauseitoffersmanypotentialadvamagessuchasformingnet-shapeparts,decreaseofmicrosegregation,reductionofporosity[1--3].Thistechnologyhasbeenappliedinproductionofsomehypo-eutectic...     

ZA27合金摩擦系数及耐磨性的试验研究

本文对未变质处理和变质处理的ＺＡ２７合金及ＺＱＳｎ６－６－３合金与ＧＣｒ１５试环进行了磨损试验研究。测量并计算了其相对摩擦系数以及合金试块间的相对耐磨性。试验研究表明：将ＺＡ２７合金进行变质处理是降低摩擦系数，提高耐磨性的有效途径。