Tool wear mechanism in turning of novel wear-resisting aluminum bronze

Tool wear and wear mechanism during the turning of a wear-resisting aluminum bronze have been studied. Tool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turn a novel high strength, wear resisting aluminum bronze without coolant and lubricant. Adhesion of workpiece materials was found on tool’s surface. Under the turning condition used in this study major wear mechanisms for turning aluminum bronze using M2 high-speed steel tool are diffusion wear, adhesive wear and plastic deformation and shear on the crater. Partial melting of high-speed steel on the rake plays a role in the tool wear also. Major wear mechanisms for turning aluminum bronze using YW1 cemented carbide tool are diffusion wear, attrition wear and sliding wear. To control the machining temperature is essential to reduce tool wear.

Effect of Fe_2B boride orientation on abrasion wear resistance of Fe-B cast alloy

The microstructures and abrasion wear resistance of directional solidification Fe-B alloy have been investigated using optical microscopy, X-ray diffraction, scanning electron microscopy and laser scanning microscopy. The results show that the microstructure of as-cast Fe-B alloy consists of ferrite, pearlite and eutectic boride. After heat treatment, the microstructure is composed of boride and martensite. The plane which is perpendicular to the boride growth direction possesses the highest hardness. In two-body abrasive wear tests, the silicon carbide abrasive can cut the boride and martensite matrix synchronously, and the wear mechanism is micro cutting mechanism. The worn surface roughness and the wear weight loss both increase with the increasing contact load. Moreover, when the boride growth direction is perpendicular to the worn surface, the highest hardness plane of the boride can effectively oppose abrasion, and the martensite matrix can surround and support borides perfectly.

Structure and properties of ceramic coatings formed on aluminum alloys by microarc oxidation

The thick and hard ceramic coatings were deposited on 2024 Al alloy by microarc oxidation in the electrolytic solution. Microstructure, phase composition and wear resistance of the oxide coatings were investigated by SEM,XRD and friction and wear tester. The microhardness and thickness of the oxide coatings were measured. The results show that the ceramic coating is mainly composed ofα-Al2O3 andγ-Al2O3. During oxidation, the temperature in the microarc discharge channel is very high to make the local coating molten. From the surface to interior of the coating, microhardness increases gradually. The microhardness of the ceramic coating is HV1800, and the microarc oxidation coatings greatly improve the antiwear properties of aluminum alloys.

Microstructure and properties of a wear resistant Al-25Si-4Cu-1Mg coating prepared by supersonic plasma spraying

A high content silicon aluminum alloy(Al-25Si-4Cu-1Mg)coating was prepared on a 2A12 aluminum alloy by supersonic plasma spraying.The morphology and microstructure of the coating were observed and analyzed.The hardness,elastic modulus,and bonding strength of the coating were measured.The wear resistance of the coating and 2A12 aluminum alloy was studied by friction and wear test.The results indicated that the coating was compact and the porosity was only 1.5%.The phase of the coating was mainly composed ofα-Al andβ-Si as well as some hard particles(Al9Si,Al3.21Si0.47,and CuAl2).The average microhardness of the coating was HV 242,which was greater than that of 2A12 aluminum alloy(HV 110).The wear resistance of the coating was superior to 2A12 aluminum alloy.The wear mechanism of the 2A12 aluminum alloy was primarily adhesive wear,while that of the coating was primarily abrasive wear.Therefore,it is possible to prepare a high content silicon aluminum alloy coating with good wear resistance on an aluminum alloy by supersonic plasma spraying.

Friction and Wear Behavior of GCr15 Under Multiple Movement Condition

Friction and wear of GCr15 under cross-sliding condition is tested on a ball-on-disc wear test machine. Thisresult shows that the cross-sliding of friction pair leads to different friction and wear behavior. For the condition de-scribed in this paper, the friction coefficients with ball reciprocating are smaller than that without ball reciprocating.The friction coefficients increase with the increase of reciprocating frequency.. The wear weight loss of the ball sub-jected reciprocating sliding decreases, however, the wear weight loss of disc against the reciprocating ball increases. Incross-sliding friction, the worn surfaces of the ball show crinkle appearance along the circumferential sliding traces.Delaminating of small strip debris is formed along the plowing traces on the disc worn surface. The plowing furrow onthe disc surfaces looks deeper and wider than that without reciprocating sliding. The size of wear particles fromcross-sliding wear is larger than those without reciprocating sliding.

捻度对渔用UHMWPE裂膜纤维线股拉伸性能与耐磨性能的影响研究

为促进超高分子量聚乙烯裂膜纤维(简称UHMWPE裂膜纤维)在渔用绳网中的应用,以膜裂法制备渔用UHMWPE裂膜纤维为原料,通过加捻制备渔用UHMWPE裂膜纤维线股,在此基础上,考察了加捻对UHMWPE裂膜线股的线密度、直径、拉伸性能和耐磨性能的影响。结果显示:UHMWPE裂膜纤维线股随捻度的增加表现出直径逐渐减小、实际线密度先增大后减小以及捻回角逐渐增加等特征;对于不同线密度规格的UHMWPE裂膜纤维线股,随着捻度的增加,其断裂强力均呈现降低的趋势,且纤维线密度越低,加捻对线股断裂强度的影响越小;1600 D的UHMWPE裂膜纤维线股的磨损次数随捻度的增加而降低,而3200和4800 D线股的磨损次数随捻度的增加呈现先降低后升高的变化趋势,且4800 D的不同捻度的线股之间的磨损次数无显著性差异(P<0.05),显示出纤维线密度越大,加捻对其耐磨性能的影响越小。1600、3200和4800 D的UHMWPE裂膜纤维线股的结节强力随捻度的增大呈现先升高后降低的变化趋势,当预加捻度为120 T·m^(-1)时,3种线密度线股的结节强力达到最大值,分别为204.15、373.5、562.41 N,较未加捻UHMWPE裂膜纤维分别提高了50.14%、37.13%和30.22%。在本实验捻度设置范围内,1600 D裂膜线股的结节强度随捻度的增加而增大,较未加捻裂膜纤维结节强度提高了32.49%。研究表明,无捻或低捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维无结网的制备;无捻或低捻度的高线密度UHMWPE裂膜纤维线股则具有较好的耐磨性能;中高捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维有结网的制备。研究结果可为渔用UHMWPE裂膜纤维绳网材料的加工、开发与应用提供参考。

铝基复合材料的力学性能及耐磨性研究

以铝粉和镁粉为基础材料,以SiC颗粒为增强体材料,制备建筑用的铝基复合材料,研究其力学性能及耐磨性。分别在SiC的质量分数为0~32%时测试铝基复合材料的力学性能,在3~18 MPa的外载荷下摩擦不同距离时,研究复合材料的耐磨性。结果表明:SiC含量较高时,复合材料中SiC团聚较明显,力学性能不佳;SiC的质量分数为8%时,铝基复合材料的硬度、抗拉强度、抗弯强度较优异;当SiC的质量分数为8%时制备的铝基复合材料在较高载荷作用下始终具有良好的耐磨性;摩擦距离越长,铝基复合材料耐磨性降低越多。

Al_2O_3·SiO_2颗粒增强铝基复合材料的摩擦磨损特性

对用挤压铸造法制备出的Al2O3·SiO2颗粒增强铝基复合材料在不同条件下的摩擦磨损特性进行了研究.结果表明:Al2O3·SiO2颗粒的加入可提高复合材料的耐磨性,复合材料同基体铝合金相比摩擦因数也较低.在较低载荷和滑动速度下,该复合材料的耐磨性明显优越于基体铝合金,摩擦因数也稳定地低于基体铝合金;而在较高载荷和滑动速度下,同基体铝合金相比,复合材料耐磨性的改善有所降低,但摩擦因数仍可以保持较低的水平.这是由于随着载荷和滑动速度的变化,复合材料的磨损机制发生了转化.对Al2O3·SiO2颗粒在摩擦磨损过程中所起到的作用进行了分析.

固溶时效对QAl9-4-3铝青铜组织和性能的影响

采用SEM、XRD、EDS、TEM、室温拉伸测试、硬度测试、摩擦学性能测试等分析手段,研究时效温度和固溶温度对自行研制的QAl9-4-3铝青铜组织和力学性能的影响。结果表明,随着时效温度的降低或固溶温度的升高,原β硬相区的马氏体特征越来越明显;固溶温度的升高还使β硬相区的面积率增大,使合金的抗拉强度和硬度增大,但降低了伸长率。获得的最佳固溶时效工艺为:(910℃,3 h)固溶后水淬+(480℃,1 h)时效后空冷。该状态下,合金中原β硬相区的显微硬度为270HV,其与α软相的面积比为71:29,使合金具有较好的强韧性配合,抗拉强度为887 MPa,硬度为253HBS,伸长率为7.3%,前两种性能分别较其挤压态合金的提高了22%和33%;其摩擦因数仅略高于挤压态合金的,但磨损率较挤压态合金的降低了27%,表现出较好的耐磨性能。

纳、微米Al_2O_3颗粒混杂增强铝基复合材料的磨损性能

利用搅拌摩擦加工（FSP）制备纳、微米氧化铝颗粒单一增强以及混杂增强的A356铝基复合材料，并在摩擦磨损试验机上考察其磨损性能。结果表明，在0．5～3．0MPa载荷范围内，在相同载荷下，混杂复合材料的磨损量都低于两种单一增强的复合材料；在不同载荷下，随着载荷的增加，复合材料的磨损量都增加，但是混杂颗粒增强复合材料的增加最快，微米颗粒增强复合材料最慢；复合材料的磨损机制主要是磨粒磨损和剥层磨损；在复合材料磨损亚表层都发现机械混合层的存在，对复合材料的耐磨性有一定的影响。

电厂飞灰颗粒增强铝基复合材料的摩擦磨损行为

对挤压铸造制成的飞灰颗粒增强ZL10 9复合材料在不同条件下的的摩擦磨损行为进行了研究。结果表明 :飞灰颗粒的加入可提高铝合金材料的耐磨性 ,复合材料同基体合金相比 ,摩擦因数也较低。在摩擦磨损过程中 ,在较低载荷下复合材料的摩擦表面形成一稳定的摩擦转移层 ,该转移层的存在可以起到降低摩擦因数的作用。在较高载荷下由于该摩擦转移层遭到破坏 ,从而影响了其减摩作用的发挥。镶嵌在基体中的飞灰颗粒在摩擦过程中主要起到承受载荷、限制对磨材料与铝基体直接接触的作用。脱落的飞灰颗粒可以起到“滚珠”的作用 ,在摩擦表面形成“三体”摩擦 ,从而起到减摩的作用。

重型车辆发动机电镀Cr活塞环的摩擦学性能

利用SRV试验机模拟重型车辆发动机电镀Cr活塞环/缸套摩擦副的工作状态,测试了不同条件下摩擦副的摩擦因数和磨损量。采用扫描电镜(SEM)、能谱仪(EDS)分析了磨痕形貌和表面化学成分,研究了电镀Cr活塞环的磨损机制。结果表明,随载荷的增加,摩擦副的摩擦因数减小,总失重量增加。随滑动频率的增加,摩擦副的摩擦因数减小,总失重量先减小后增加,滑动频率为20Hz时,总失重量达到最小值。随温度的升高,摩擦副的摩擦因数增大,总失重量增加。活塞环和缸套的磨损机理以磨粒磨损为主,在高载荷,高频率或高温条件下,活塞环的磨损机理转变为磨粒磨损和黏着磨损。

Al对ZG40Cr25Ni20耐磨性的影响

对Al含量为0、1.68%、4.72%和7.10%的ZG40Cr25Ni20进行了对比磨损试验。结果表明,Al的加入可以不同程度的提高材料的耐磨性能,Al含量为7.10%时耐磨性最好,其在相同条件下的耐磨性为不含Al时的2.62倍,其次为Al含量为4.72%,其耐磨性比Al含量为1.68%时提高66.40%,试验合金的磨损机理为微观切削。

衬板用铸态Fe-24Mn-7Al-1C耐磨钢的应变硬化行为研究

对衬板用新型铸态轻质Fe-24Mn-7Al-1C耐磨钢进行准静态条件下不同变形量的压缩试验,分析应变硬化行为,揭示出该铸态耐磨钢的加工硬化机理。根据压缩应力-应变曲线和对数真应力-对数真应变曲线分析压缩变形特征;并利用光学显微镜、X射线衍射和透射电镜研究不同应变量的变形后的微观组织形貌。研究结果表明,试验钢在屈服阶段的加工硬化曲表现出双加工硬化指数行为;在透射电子显微镜和X射线衍射分析时既未发现形变诱发马氏体存在,也没有发现位错胞和形变孪晶,变形后仍为奥氏体单相组织;在不同变形量变形后的奥氏体显微组织中依次可以观察到位错堆积(1%)、高密度位错墙(5%)、泰勒晶格(10%)、具有高密度位错的畴界(20%)和微带(50%),说明轻质Fe-24Mn-7Al-C耐磨钢钢微观变形机理是平面滑移机制。

合金化对汽车活塞用铸造铝合金的组织和性能影响

研究了添加V、Co元素合金化对汽车活塞用铸造铝合金Al-10Si-0.3Mg铸造性能的影响,并进行了不同元素合金化下的显微组织、力学性能和耐磨损性能的测试和分析。结果表明:与未添加V、Co合金化的试样性能相比,复合添加0.3%V、0.3%Co试样的抗拉强度和断后伸长率增幅分别为8%、27.85%,磨损体积则减小29.63%。复合添加V、Co合金元素后,合金的晶粒得到细化,力学性能和耐磨损性能显著提升。

Sn含量对WC基金刚石钻头的性能影响研究

文章以WC-Cu-Co基金属结合剂为基础,研究Sn含量对结合剂性能的影响。对不同Sn含量配方的三点抗弯强度、磨损失重、硬度进行了测试,最后通过微钻实验验证实际钻进效果。研究结果表明:随着Sn含量的增加,胎体的三点抗弯强度τ0、磨损失重Δm值和硬度HRB均呈现出先上升然后逐渐下降的趋势,Sn含量为4%左右时,胎体具有最好的力学性能和最小的磨损失重。微钻实验进一步验证了Sn含量为4%的钻头配方具有较长的寿命和较高的效率。

喷射轧制钢/Al-Pb复合轴瓦带材的组织与性能

采用喷射轧制工艺制备了钢/Al-8.5Pb-4Si-Cu O.5Sn复合轴瓦带材,分析了所制备材料的组织及性能.结果表明,用喷射轧制工艺制备的轴瓦合金Al-Si基体中分布有均匀细小的Pb相粒子,经过50％变形量的轧制和在320℃后续退火5h的处理,在复合轴瓦带材的界面处发生了合金元素的扩散,形成了良好的冶金结合层,界面强度高,剪切强度达到72 MPa.用喷射轧制工艺制备的轴瓦合金具有良好的耐磨性能.

新型高摩合成材料组分对摩擦性能的影响规律研究

采用正交试验设计的方法制备得到不同配比的新型高摩合成材料,通过极差分析方法探索了组分对合成材料摩擦系数、弹性模量的影响规律。在MMS-2A摩擦磨损试验机上测试了材料的摩擦系数,用OLS4100型-3D激光共聚焦显微镜观察了摩擦试样的磨损形貌,探索分析了组分影响合成材料摩擦磨损性能的内在机理,并用TG/DTA7300型号热分析仪和SANS试验机对合成材料的热性能及力学性能进行测试,获得组分对各种性能的影响规律。结果表明:高性能填料与丁腈橡胶对材料的摩擦系数影响最大,纤维影响最小;纤维对弹性模量的影响最明显,影响最小的是高性能填料。建立了模型摩擦系数与弹性模量的回归模型,其R2值分别为0.94与0.955。合成材料开始分解的温度在300℃左右,材料的耐热性能随着橡胶含量的增加而降低。通过对表面形貌进行分析,发现不同的组分对合成材料磨损机制的影响规律。

铸造工艺对机械叶轮铝合金性能的影响

采用不同的浇注温度对ZL102-0.15%Ti-0.1%Sr铝合金机械叶轮进行了铸造,并进行了耐磨损性能和冲击性能的测试与分析。结果表明：与常规消失模铸造的优化工艺相比,机械振动消失模铸造叶轮的磨损体积减小25%、冲击韧性增大22%,叶轮的耐磨损性能和冲击性能明显提高。叶轮的铸造工艺优选为机械振动消失模铸造。

Fe_3Al基复合材料的制备及其摩擦磨损行为

用球磨机械合金化工艺制备Fe3Al粉末 ,采用粉末冶金工艺 ,选择不同的烧结温度和烧结压力 ,获得了Fe3Al基复合材料。对材料的物理力学性能、摩擦磨损性能和微观结构进行分析测试 ,借助磨损表面扫描图像 ,分析了该材料的磨损形式 ,探讨了其磨损机理。结果表明 :在烧结温度为 1 0 5 0℃ ,烧结压力为 1 0～ 1 5MPa的工艺条件下制得的Fe3Al基复合材料有较好的摩擦磨损性能。其摩擦机理为 :疲劳磨损和磨粒磨损为主 ,兼有磨粒和粘着磨损混合形式。