冷却速度和铅含量对新型Al-Pb铸造轴承合金显微组织的影响

采用一种新的铸造技术将较多的铅混合到铝合金中,然后用普通的浇铸方法制备铸造铝铅合金。利用光学显微镜、扫描电镜、定量金相等技术研究了冷却速度、铅含量、重力作用等对铝铅合金显微组织的影响。结果表明：用该技术制备的铝铅合金中的铅颗粒呈团絮状均匀分布于基体内,铅颗粒的尺寸随铅含量的增加而增加,随冷却速度的增加而减小。     

铸造铝铅滑动轴承合金的制备及其显微组织

利用一种新的铸造技术，使高达４０％的铅混合到铝合金中，然后用普通的浇铸方法生产铸造铝－铅合金。在实验中，探讨了其最佳工艺参数，并利用光学显微镜，扫描电镜，定量金相等技术研究了铝含量和合金元素对其显微组织结构的影响。     

稀土对两种青铜的铸态组织和某些性能影响的研究

研究了不同稀土对７－１３－４－１铝青铜（无镍高锰铝青铜）产ＺＣｕＰｂ６Ｓｉ３Ｍｎ（含铅硅青铜）的铸态组织、流动性、耐磨性和耐蚀性的影响。结果表明，适量稀土可以细化合金的铸态组织，大大改善合金中铅的偏析；两种合金的标准螺旋形式样长度分别增加１０７－１１２％和４５－８５％，靡损量分别－７０％和３８－５５％，腐蚀量分别减少４０－５０％和３５－５０％；并探讨了出现这种变化规律的原因。     

不同压力下挤压铸造铝铜合金的组织与性能

采用挤压铸造工艺制备出一种新开发的、高强韧铝铜合金.T5热处理状态下其抗拉强度达到433 MPa,伸长率为14%.通过对该合金力学性能及其显微组织的研究表明,铸态和经T5热处理的抗拉强度和伸长率均随压力的增加而增大,在压力为50MPa时达到最大值,但在铸态下,未加压力的铸造合金其硬度高于挤压铸造的合金硬度.随挤压力增加,晶粒明显细化,二次枝晶增加,枝晶间距减小.     

搅拌摩擦加工铸态铝铁合金组织和性能研究

采用搅拌摩擦加工技术对含铁3％(质量分数)铸态铝铁合金进行3道次往复搅拌摩擦加工,研究加工区显微组织和力学性能的变化.结果表明,铸态铝铁合金经搅拌摩擦加工后,粗大的针状Al3Fe相被破碎成细小粒状,铸态组织转变成低位错密度的再结晶组织,且基体中存在细小的含铁亚稳相.搅拌摩擦加工后,加工区的显微硬度较铸态区降低,但分布比较均匀;加工区合金的抗拉强度稍微下降,延伸率显著增大.经搅拌摩擦加工后,合金拉伸断口呈现出微孔聚合韧性断裂特征.     

铸态铸造铝硅合金的现状和发展

介绍了铸态铸造铝硅合金的重要性及铸态铸造铝硅合金的发展概况;列举了国内、国外为提高铸态铸造铝硅合金力学性能研究的方法和内容,提出展望。     

铝铅轴承合金与热浸铝钢板的热轧复合机制与结合强度

铝铅轴承合金带与具有不同厚度化合物层的热浸铝钢板通过热轧成功实现复合。复合界面结构分析表明：复合过程中形成两种界面，热浸铝钢板与铝铅合金带通过化合物界面结合与缺口界面结合的机制而复合，阐述了热浸时间，化合物层厚度，缺口界面分数之间的关系以及对结合强度的影响，其中缺口界面分数是影响结合强度的主要因素，结合强度与缺口界面之间呈线性关系，缺口界面分数随化合物厚度的增加而增加，超过73μm，转为下降。     

微量钪对ZAlSi7Cu2Mg合金铸态组织与性能的影响

通过采用电子万能试验机、金相显微镜以及扫描电镜,分析研究了微量钪对铸造铝硅合金铸态组织与性能的影响规律.结果表明:当添加钪的含量(wSc)达到0.15％时,合金的铸态组织发生了显著的变化,当钪的含量达到0.2％时,铸态铝硅合金的力学性能达到了最大值,随着钪含量的继续增加,合金的力学性能呈下降趋势.     

原位反应铸造半固态7075铝基复合材料的组织

采用原位反应液相线铸造方法制备了含有不同体积分数TiC颗粒的7075半固态铝基复合材料，通过光学显微镜和透射电镜观察其铸态组织，并利用平均截线法测量晶粒尺寸，研究原位颗粒对液相线铸造半固态铝合金组织的影响。结果发现，原位TiC颗粒对半固态铝合金的铸态组织产生细化和球化作用，当原位TiC颗粒体积分数达到2．5％时，材料能够得到等轴晶组织，对应的平均晶粒尺寸为35．6μm。     

稀土元素Ce对ZM21镁合金组织和力学性能的影响

通过传统的半连续铸造方法制备了Mg-2Zn-Mn-xCe(x=0,0.1,0.3,0.7,质量分数,%)合金。采用金相观察、XRD、扫描电镜、断口分析以及室温拉伸试验研究了Ce加入量对铸态和挤压态的ZM21镁合金显微组织和力学性能的影响。结果表明:随着Ce含量的增加,铸态ZM21+xCe合金中,聚集在枝晶间隙的Mg-Ce相和Mg-Zn相逐渐增多,最终形成连续的网状结构;在热挤压过程中,大部分含Ce第二相被压碎,弥散分布在基体中。随着Ce含量的增加,铸态合金的强度和塑性都先下降后上升;经挤压后,合金的强度和伸长率都得到大幅度提高,尤其是添加0.57%的Ce后,伸长率达到24%。     

Friction and wear characteristics of hot-extruded leaded aluminum bearing alloys

The friction and wear characteristics of hot-extruded Al-Pb alloys with lead contents in the range 0–25 wt.% and as-cast Al-Pb alloys with lead content of 20 wt.% were investigated under dry-sliding conditions using a pin-on-disc test machine. It was found that hot extrusion greatly decreased the porosity that was caused by powerful stirring and considerably improved the mechanical properties of stircast Al-Pb alloys, including wear behavior. The coefficient of friction and wear rate decreased with increasing lead content, and especially the antiseizure property of hot-extruded Al-Pb alloys containing 20 wt.% and 25 wt.% lead were improved remarkably. Optical observation revealed that the reason for this was the formation of a black compact film of lubricant that covered almost the entire worn surface of specimens at a highly applied load level. This film is a mixture of different constituents containing Al, Fe, Si, O, and Pb.     

Surface modification of Al-Pb alloy by high current pulsed electron beam

Al-Pb alloy was modified by high current pulsed electron beam and the microstructure, hardness and tribological characteristics were characterized by scanning electron microscopy, electronic microanalysis probe microanalysis, Knoop hardness indentation and pin-on-disc type wear testing machine. The results show that the microstructure and hardness can be greatly improved, and the modification layer consists of a molten zone, an overlapped zone of heat-affected and quasistatic thermal stress-affected zone and a transition zone followed by the substrate. The tribological properties of high current pulsed electron beam irradiated Al-Pb alloy are correspondingly improved largely. Optical observation and scanning electron microscopy analysis reveal that the low wear rate and lowest level in coefficient of friction at high load level for irradiated Al-Pb alloy are due to the formation of a lubricious tribolayer covering the worn surface, which is a mixture of Al2O3, Pb3O4 and silicate. The wear mode varies from oxidative wear at low load to film spalling at high load and, finally, adhesive wear.     

半固态成形制备铝铅难混溶合金

通过机械搅拌半固态成形技术制备铝铅系难混溶合金.研究了温度对该合金铅颗粒晶粒尺寸和分布及固相率的影响.微观结构观察表明:通过强力的机械搅拌,可以把铝铅合金中的铅颗粒弥散均匀分布于基体合金中.随着温度的降低:合金的固相率增大,从630℃开始凝固到585℃合金固相率升到67%,呈非线性变化;初生α-Al颗粒在机械搅拌的作用下变得圆整;铅颗粒粒度趋于减小,分布分布趋于均匀、一致,与温度之间同样呈非线性变化;合金中铅含量测试表明,铅的含量处于5.80%左右.说明可利用机械搅拌结合半固态成形技术制备铝铅系难混溶合金.     

Abrasive wear behavior of Ni-P coated Si3N4 reinforced Al6061 composites

Ni-P coated Si₃N₄ reinforced Al6061 composites were fabricated by vortex method. Percentage of reinforcement was varied from 6 wt.% to 10 wt.% in steps of 2. Cast matrix alloy and developed composites were hot forged at a temperature of 500 °C using a 300T hydraulic hammer. Both as cast and hot forged matrix alloy and its composites were subjected to microstructure studies, grain size analysis, microhardness and abrasive wear tests. Microstructure studies reveal uniform distribution of silicon nitride particles with good bond between matrix and reinforcement in both as cast and hot forged condition. It is observed that, increased content of reinforcement in both as cast and hot forged composites do result in significant grain refinement. However, when compared with as cast matrix alloy and its composites hot forged alloy and its composites exhibits higher extent of grain refinement. Both as cast and hot forged composites exhibit improved microhardness and abrasive wear resistance when compared with the unreinforced alloys under identical test conditions. Abraded worn surfaces were examined using scanning electron microscopy (SEM) for possible wear mechanisms. Increased abrasive particle size and load has resulted in larger extent of grooving leading to increased abrasive wear loss for both the matrix alloy and developed composites.     

机械合金化制备的Al-Pb-Cu合金结构与摩擦性能

用机械合金化方法制备了Al-Pb-Cu合金。X射线衍射（XRD）和扫描电镜（SEM）分析表明，随机械合金化的进行，Al-Pb-Cu合金中相继有Cu9Al4和CuAl2相形成，在随后的烧结过程中，CuAl2相农渐增加，而Cu9Al4相逐渐消失，最终获得了在Al基体上弥散分布为Pb相和CuAl2相的组织，与Al-Pb二元合金相比，Cu的加入在一定程度上抑制了Pb相的长大，摩擦磨损性能测定表明，Al-Pb-Cu合金的摩擦磨损性能比相同方法制备的Al-Pb二元合金有了较大提高，当Cu含量（质量分数）为4．5％时，合金的耐磨性最佳。     

快速凝固(2024Al)-20Si-5Fe合金的磨损行为

采用双级雾化水冷快凝与粉末冶金技术制备了（2024Al)-20Si-5Fe(质量分数.%)耐磨合金。分析了合金的微观组织。利用磨损实验研究了合金的耐磨性和磨损失效形式。结果表明：快凝粉末冶金合金具有比铸造合金更细小的微观组织。更高的耐磨性和减磨性。耐磨性是铸造合金的2．5－4倍。快凝合金的磨损失效形式主要是磨粒磨损和疲劳磨损。耐铸造合金的磨损失效形式主要是磨粒磨损、粘着磨损和部分氧化磨损。     

Fabrication of sintered Zn—27% Al and comparison of its tribological behavior with cast alloy

High quality Zn-base powder with low oxygen content,fine particle size and fine microstructure can be obtained by gas atomization using nitrogen.Cast and sintered Zn-27%Al alloys(ZMJ)were prepared.Tribological behaviors or the cast and sintered alloys under lubricated and non-lubricated conditions were studied and compared.Worn surfaces of the cast and sintered alloys under lubricated and non-lubricated conditions were studied and compared.Worn surfaces and microstructures of these alloys were examined.Results indicate that although the srength of the sintered alloy is considerably less than that of the cast alloy,the sintered alloy has a better wear resistance.The fine microstructure obtained by rapid solidification is beneficial to the wear-resisting property.The wear volume of sintered ZMJ is only 36% and 59% of the wear volume that found in cast ZMJ under non-lubricated and lubricated conditions,respectively.For lubricated wear test,abrasive wear is the major wear mechanism and for non-lubricated wear test,oxidation wear and adhesive wear are the major wear mechanisms.     

热变形对多元合金耐磨铸铁组织和性能的影响

研究了热变形量对多元合金耐磨铸铁组织和冲击韧度的影响，结果表明，热变形能改变耐磨铸铁组织中共晶碳化物的形状与分布，促进颗粒状碳化物的析出，提高耐磨铸铁的冲击韧度。当该耐磨铸铁的热变形量为40％时，其冲击韧度最佳。     

新型低合金耐磨耐蚀铸铁的开发与应用

通过对不同成分的Cr,Cu,Sb低合金耐磨耐蚀铸铁的研制,获得在合金总量不超过3%,而其耐磨耐蚀性能较好的低合金耐磨耐蚀铸铁NMSHT9。实际应用表明,它是一种价格低廉、性能良好的耐磨耐蚀铸铁。     

Influence of carbides morphology on the mechanical properties for Fe-C-V alloys

The paper presents the results of tests on the spheroidising treatment of vanadium carbides VC done with magnesium master alloy and RE. The conducted metallographic studies have shown that introducing the magnesium master alloy to an Fe–C–V system of eutectic composition causes the crystallisation of spheroidal carbides. The content of these carbides is about 5.6%, representing 33% of all the crystallised vanadium carbides. Adding RE to the base alloy melt caused 31% of the vanadium carbides crystallise as dendrites. Testing of mechanical properties has proved that the spheroidising treatment of VC carbides in high-vanadium cast iron increases the tensile strength by about 60% and elongation 14–21 times, depending on the type of the spheroidising agent used. Tribological studies have shown that high-vanadium cast iron with eutectic, dendritic and spheroidal carbides has the abrasive wear resistance more than twice as high as the abrasion-resistant cast steel.