不同摩擦层对TC11合金干滑动摩擦磨损行为的影响

通过在TC11合金/GCr15钢摩擦界面上添加各种纳米材料而形成不同摩擦层,研究其对TC11合金磨损行为的影响,并与未添加纳米材料时进行对比。采用X射线衍射仪(XRD)、拉曼光谱仪(Raman)、扫描电镜(SEM)、能谱仪(EDS)等微观分析手段对磨面物相、形貌和成分进行了分析,并探讨了各摩擦层的作用机制。结果表明:只添加Fe_2O_3纳米颗粒时形成的单层摩擦层在二次磨损中不能起到保护作用,与TC11合金自身一样具有较差的耐磨性。添加MoS_2与Fe_2O_3机械混合材料时,在磨面形成机械混合摩擦层,添加多层石墨烯(MLG)/Fe_2O_3复合材料、MLG与Fe_2O_3机械混合材料时,形成双层摩擦层,但两种双层摩擦层在结构上存在差异性。这些摩擦层均能在一定程度上起到保护作用,使得TC11合金的耐磨性得以提高。特别地,添加MLG与Fe_2O_3机械混合材料形成的上、下层基本为MLG、Fe_2O_3的双层摩擦层,因其分别具有优良的润滑性能与良好的承载能力,能最高效地改善TC11合金的耐磨性。     

La_2O_3对微波烧结Cu_(20)Fe_(80)合金组织性能的影响

采用机械合金化和冷压微波烧结法制备了Cu_(20)Fe_(80)合金,研究了La_2O_3添加对Cu_(20)Fe_(80)合金组织性能的影响,利用扫描电子显微镜和X射线衍射仪等设备观察和分析Cu_(20)Fe_(80)合金组织形貌和相组成,并测定了合金的致密度和硬度。结果表明:Cu_(20)Fe_(80)合金粉体呈层片状,随La2O3质量分数的增加,合金粉体得到细化,机械合金化程度增强;Cu_(20)Fe_(80)合金粉体的冷压压坯组织呈层片状,随La_2O_3质量分数的增加,压坯致密程度和成型性提高;微波烧结后组织呈现层片状,随La_2O_3质量分数的增加,空隙先减少后增加,烧结组织致密度和硬度先提高后减小;综合分析,La_2O_3最佳添加量为0.2%。     

稀土Y对Ni-Fe-Co-Cu合金微观组织和高温氧化性能的影响

研究了稀土Y对45Ni-40Fe-8Co-7Cu合金微观组织和850℃高温氧化性能的影响。结果表明,45Ni-40Fe-8Co-7Cu合金在850℃,0.101 MPa氧分压下氧化形成以Fe_2O_3和(Ni/Co)Fe_2O_4为主的混合氧化物膜层,合金氧化遵循抛物线规律,抛物线速率常数为1.83×10~(-10)g~2·cm~(-4)·s~(-1)。添加稀土Y后,合金沿晶界析出稀土相,Y含量越高,晶界稀土相越多。添加稀土后的合金在850℃高温氧化过程中,氧化仍遵循抛物线规律,同时,晶界稀土相促进了Ni的外扩散,氧化形成的膜层以(NiCo)Fe_2O_4尖晶石氧化物为主。添加0.3%(质量分数)稀土Y的45Ni-40Fe-8Co-7Cu-0.3 Y合金850℃高温氧化形成的尖晶石结构的氧化物结晶颗粒细小,膜层致密完整,且合金抛物线氧化速率常数减小为1.15×10~(-10)g~2·cm~(-4)·s~(-1),说明添加少量(0.3%)稀土Y后,细化了氧化物结晶颗粒,提高了合金抗氧化性能。随着稀土Y添加量的进一步增加,合金高温氧化过程中,晶界稀土相不但促进了Ni的外扩散,同时加速了O的内扩散,合金抗氧化性能变差。     

机械模具导向滑板Fe-Mo-石墨自润滑材料摩擦学性能研究

采用粉末冶金工艺,制备了3种不同石墨含量的Fe-Mo-石墨自润滑材料,测定了3种材料的密度、硬度和抗压强度,并对材料的组织和不同摩擦速率下的摩擦学性能进行分析和研究,最后采用扫描电镜(SEM)和X射线衍射仪(XRD)对磨痕表面形貌和成分进行表征。结果表明,复合材料中石墨添加质量分数为1.0%时,材料组织以铁素体为主相,此时的摩擦系数较为稳定,磨损率随摩擦速率的提高而增大,磨损机制主要为粘着磨损;石墨添加质量分数高于1.0%时,材料组织以珠光体为主相,摩擦系数随摩擦速率提高而增大,但磨损率随之减小,且摩擦速率高于0.5m/s时,磨损率量级为10~(-8)cm~3/N·m,属于轻微磨损。材料中珠光体、Fe_2MoC的生成,以及摩擦过程中生成的Fe_2O_3、Fe_3O_4是Fe-Mo-石墨材料在高的摩擦速率下具有优良耐磨性的主要原因。     

银/石墨烯复合润滑添加剂对于润滑油摩擦性能的影响

通过化学还原合成了银包覆石墨烯(Ag/RGO)复合添加剂, 利用X射线衍射仪和扫描电镜分析了样品相成分和微观形貌, 采用UMT-2摩擦磨损试验机测定了Ag/RGO复合润滑油添加剂的摩擦性能。结果表明: 纳米银颗粒均匀分布在石墨烯片上, 银颗粒的粒径大约200nm。在摩擦磨损试验过程中, 摩擦副与磨损表面的凹凸点直接接触, 纯润滑油的润滑作用较差; 在润滑油中添加Ag/RGO复合添加剂, 在摩擦初始过程中, 摩擦副与磨损表面也是凹凸点直接接触, 随着磨损时间的增加, Ag/RGO复合添加剂在摩擦副与磨损表面之间形成一层润滑膜, 阻隔摩擦副与磨损表面直接接触, 产生边界润滑; 另外, 部分纳米银颗粒可起到微轴承作用, 使得改性后的润滑油润滑性能更好。     

TC4合金在不同环境介质中的磨损行为及磨损机制研究

采用MPX-2000型销盘式摩擦磨损试验机,研究了TC4合金在空气、纯水和模拟海水环境下与GCr15轴承钢对磨时的磨损行为和磨损机制,评价不同环境介质对TC4合金耐磨性的影响。结果表明:TC4合金在模拟海水中的磨损率始终最高,明显高于其在纯水和空气中的磨损率,且在模拟海水中磨损时TC4合金腐蚀速度大大加快,可见腐蚀和磨损之间存在明显的相互促进作用。TC4合金在模拟海水中形成的润滑膜可以明显降低摩擦系数,因而不同工况下模拟海水中的摩擦系数始终较低,纯水中的摩擦系数略高于海水,而空气中的摩擦系数在0.50及0.75 m·s-1,1.02 MPa时明显高于纯水和海水,在0.75 m·s-1,2.55 MPa时反而略低于纯水和模拟海水。TC4合金在空气中的磨损机制为氧化磨损并伴有一定程度的磨粒磨损和粘着磨损;在纯水中的磨损机制为磨粒磨损;而在模拟海水中则为疲劳磨损和磨粒磨损混合作用机制。     

镁锂合金表面含碳陶瓷层的摩擦性能

通过在Na₂SiO₃-KOH基础电解液中加入石墨烯添加剂,在镁锂合金表面制备出一层自润滑的含碳陶瓷层. 利用扫描电镜、原子力显微镜以及X射线衍射仪分析了陶瓷层的表面形貌、粗糙度以及物相组成,利用摩擦磨损试验仪对陶瓷层在室温下的摩擦学性能进行研究. 其结果表明,加入石墨烯后制备出的含碳陶瓷层表面放电微孔分布均匀,且其微孔尺寸和表面粗糙度均明显降低. 相比于镁锂合金,陶瓷层的表面硬度也得到明显的提高. 此外,含碳陶瓷层主要由SiO₂、Mg₂SiO₄以及MgO物相组成,而石墨烯则以机械形式弥散分布于陶瓷层中并起到减摩作用. 当石墨烯体积分数为1%时,陶瓷层表面显微硬度为1317.6 HV_{0.1 kg},其摩擦系数仅为0.09,其耐磨性明显提高. 同时,陶瓷层磨痕的深度和宽度均明显小于镁锂合金,而且较为光滑,表明陶瓷层表面没有发生严重的黏着磨损.      

掺硅非晶碳薄膜对TC4摩擦磨损性能的影响

利用C₂H₂和Si靶,通过等离子体增强化学气相沉积(plasmaenhancedchemicalvapordeposition,PECVD)和磁控溅射法,在Ti-6Al-4V(TC4)合金表面沉积类金刚石(diamond-likecarbon,DLC)膜层和不同Si含量的Si-DLC膜层。利用拉曼光谱和X射线光电子能谱分析膜层中的键合含量和结构无序性;采用纳米压痕和纳米划痕法测试TC4合金及其膜层试样的力学性能;使用HT-1000高温摩擦磨损测试仪和光学轮廓仪测试TC4合金及其膜层试样的摩擦磨损性能。结果表明：无论是否含Si元素,DLC膜层都能够有效提高TC4基体表面硬度,其中沉积纯DLC膜层后TC4基体的硬度相比无涂层提升了2.4倍,提升率最大;纯DLC和Si的摩尔分数分别为1.79%和3.06%的2种Si-DLC膜层,都可使TC4基体的表面摩擦因数从无涂层的0.64降低至0.1左右,磨损率从无涂层的476.5×10^-7 mm³/(N·m)降低至0.5×10^-7 mm     

Ni元素对Al-Cu-Mn合金组织及力学性能的影响

为研究添加Ni元素对Al-5.0Cu-0.6Mn合金组织及力学性能的影响,通过硬度试验、拉伸力学试验及摩擦磨损试验对合金力学性能进行研究;采用扫描电子显微镜、激光共聚焦显微镜及透射电子显微镜对合金微观组织进行检测分析。结果表明：向Al-5.0Cu-0.6Mn合金中添加Ni元素后,由于Al₃CuNi相析出的强化作用,并且与基体结合良好的增强相颗粒能均匀分布于合金中,使得合金硬度和强度大幅提高,摩擦磨损深度显著降低,综合力学性能得到有效的提升。当Ni元素的添加量为0.3%(质量分数)时,由于T相(Al₂₀Cu₂Mn₃)和Al₃CuNi相分布比较均匀,合金综合性能较为理想,其HV硬度、抗拉强度、摩擦磨损系数分别为126.4 MPa、395.2 MPa、0.12。     

铜熔炼渣中隔膜层形成与金属损失

利用高温X射线透射电视技术,在实验电炉中对工业炼铜炉料的冰铜熔炼过程进行了研究。当产出高品位冰铜和低SiO_2/Fe渣时,渣中形成夹有Fe_3O_4晶粒的隔膜层。炉料中含有较高的锌和Al_2O_3时,渣中易形成夹有尖晶石析出物的隔膜层。隔膜层的形成引起了渣含铜升高,熔炼时易产生泡沫渣。     

Effect of artificial tribological layer on sliding wear behavior of H13 steel

An artificial tribological layer was formed on the worn surface during sliding, through supplying MoS2 , Fe2 O 3 or their equiponderant mixtures onto the sliding interface of H13/GCr15 steels.The effect of this tribological layer on the wear behavior of H13 steel was studied.The worn surfaces and subsurfaces of H13 steel were thoroughly characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS); the wear mechanisms were explored.The research results demonstrated that tribological layer did not exist during sliding of H13 steel with no additive, but it formed with the addition of MoS2 , Fe2 O 3 or their equiponderant mix-tures.When there was no tribological layer, the wear rate rapidly increased with an increase of the load.In this case, adhesive and abrasive wear prevailed.As the additives were supplied, the artificial tribological layer was observed to be immediately formed and stably existed on worn surfaces.This tribological layer presented an obvious protective function from wear and friction.Hence, the wear rate and friction coefficient were significantly decreased.MoS2 as tribological layer seemed to present more obvious protective function than Fe2 O 3 .By supplying their mixture, the artificial tribological layer possessed not only the load-carrying capacity of Fe2 O 3 , but also the lubricative capacity of MoS2 .These two simultaneous capacities could improve the friction and wear properties of H13 steel further.     

Effect of Various Nanoparticles on Tribo-Layers and Wear Behavior of TC11 Alloy

Multilayer graphene (MLG), Fe₂O₃, and their nanocomposites with various proportions and amounts were applied as additives and directly participated in the formation of tribo-layers during sliding wear of TC11 alloy against AISI 52100 steel. Their ingredients and amounts were found to exert substantial effects on the additive-containing tribo-layers and wear behavior. Irrespective of the added amount of MLG or Fe₂O₃, the formed tribo-layers, because of the lack of load-bearing or lubricant capacity, readily lost stability and protection function, causing a high wear rate. However, a small quantity of MLG/Fe₂O₃ nanocomposites could result in a remarkable decrease in the wear rate. This was attributed to the stable existence and continuous protection of a friction-reduced and wear-resistant double-layer tribo-layer. In particular, Fe₂O₃-rich nanocomposite additives produced more protective tribo-layers to markedly improve the wear resistance of TC11 alloy.     

MA-SPS制备超细晶Ti-8Mo-3Fe合金的摩擦磨损性能

以机械合金化+放电等离子烧结（MA-SPS）制备的超细晶Ti-8Mo-3Fe合金为研究对象,研究了合金在模拟体液（SBF）中的摩擦磨损性能,并与放电等离子烧结制备的微米尺寸晶粒的Ti-8Mo-3Fe合金、铸造纯Ti及Ti-6Al-4V （TC4）合金进行了对比.结果表明:采用MA-SPS工艺可制备出高致密度、组织均匀的超细晶Ti-8Mo-3Fe合金,合金由β相及少量α相组成,平均晶粒尺寸为1.5 μm,显微硬度为448 HV;在相同摩擦磨损条件下,超细晶Ti-8Mo-3Fe合金的摩损程度明显低于微米晶粒Ti-8Mo-3Fe和铸态的纯Ti及TC4合金,具有最低的磨损体积和较稳定的摩擦系数.超细晶Ti-8Mo-3Fe合金的磨损机制为磨粒磨损,而微米晶粒Ti-8Mo-3Fe和铸态纯Ti及TC4合金的磨损机制为磨粒磨损和黏着磨损并存的混合磨损.      

WC对金刚石钻头镍基钎料胎体性能的影响

在Ni-Cr-B-Si基钎料中添加WC,添加量(质量分数)不超过30％.对胎体材料的硬度、抗弯强度和耐磨性进行测定,用扫描电镜观察胎体的表面形貌,并对不同区域进行能谱分析.结果表明,随w(WC)增加,胎体材料的硬度和耐磨性先增大后减小,在w(WC)为20％时,硬度达到最大值(123.8HRB),耐磨性最好,磨损量为0....     

Effect of Microstructures on Resistance of a Hot Elevated-Temperature Wear Working Die Steel

 Elevated-temperature wear tests under atmospheric conditions at 400 ℃ were performed for a hot working die steel H21 on a pin-on-disk wear tester. The phase and morphology of worn surfaces were examined using XRD and SEM, and the relation of wear resistance to tempered microstructures was studied for H21 steel. XRD patterns exhibit that oxidative wear is a predominated wear mechanism with Fe3O4 and Fe2O3 on worn surfaces. It is found that with increasing normal load, obvious plastic deformation of substrate appears on worn surfaces. Microstructures start to affect apparently wear resistance of the steel with an increase of load. Under loads of 50-100 N, wear losses of steel retain low values and relatively approach for steels with various microstructures. As loads are increased to 150-200 N, wear losses of steel start to increase obviously and present apparent difference for steel with various microstructures. Wear resistance is found to increase in the sequence as follows: tempered sorbite, tempered martensite, tempered troostite without secondary hardening and tempered troostite with secondary hardening or upcoming one. Higher strength and microstructural stability are required for steels with excellent wear resistance.     

Influence of La2O3 addition on microstructure and wear resistance of Fe-Cr-C cladding formed by arc surface welding

The Fe-Cr-C claddings formed by arc surface welding with different La2O3 additions were investigated. The microstructures were observed by optical microscopy (OM), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The phase structures were measured by X-ray diffraction (XRD). The wear resistances of the claddings were tested by friction and wear experiment. On this basis, the carbide refinement mechanism by inclusion enriched with La was discussed theoretically. The results showed that, the microstructure of the Fe-Cr-C cladding consisted of primary (Cr,Fe)7C3 carbides and eutectic (γ-Fe+(Cr,Fe)7C3 ) structure. With La2O3 addition increasing, the primary carbides were refined, and the mass loss of the cladding decreased gradually. The Fe-Cr-C cladding with 4wt.% La2O3 addition had a best wear resistance behaviour. The RE inclusion LaAlO3 as heterogeneous nuclei of the primary M7C3 was medium effective, and could refine the M7C3 carbides. Besides, the wear resistance could be improved by adding La2O3 in the claddings.     

NC30Fe合金在氯化钠溶液中的微动腐蚀特性

在PLINT微动磨损试验机上附加电化学测试系统,采用十字交叉接触方式,位移幅值为100μm,法向载荷20、50和80 N条件下,研究NC30Fe合金传热管在氯化钠溶液中的微动腐蚀行为.使用电化学工作站记录微动腐蚀过程中开路电位变化,运用电位扫描法测量微动过程的极化曲线;采用扫描电子显微镜观察磨痕的表面形貌,光学轮廓仪测定磨痕的三维形貌及磨损量.微动磨损使损伤区域金属原子活性增大,腐蚀倾向增大,加速了NC30Fe合金的腐蚀.在氯化钠溶液中,NC30Fe合金由于微动磨损过程产生腐蚀产物膜起到润滑减摩作用,摩擦系数较纯水中降低;但因腐蚀与磨损的交互作用,在氯化钠溶液中的磨损量比纯水中高.氯化钠溶液中的磨损机制主要表现为磨粒磨损和剥层的共同作用.      

Research on Thermal Wear of Cast Hot Forging Die Steel Modified by Rare Earths

Thermal wear of cast hot-forging die steel modified by rare earths（RE） was studied and compared with commercially used die steels. The function of RE and the mechanism of thermal wear of cast steel modified by RE were discussed. The results showed that with increasing content of RE, the wear rate of cast steel reduced at first and then increased. By adding 0.05% （mass fraction） RE, the cast hot-forging die steel with optimum thermal wear resistance was obtained, which was better than that of H13 and 3Cr2WSV. The large amount of coarse inclusions, （RE）2O2S, resulted from excessive RE, which obviously deteriorated thermal wear resistance. The mechanism of thermal wear of the modified cast die steel is oxidation wear and oxide fatigue delamination. The wear debris are lumps of Fe2O3 and Fe3O4.     

Al-Zn-Mg合金高温摩擦磨损行为研究

采用高温摩擦磨损试验机,在25～500℃的试验温度和1～5 N法向载荷下对Al-Zn-Mg合金进行球盘摩擦试验,分析不同试验温度和法向载荷下Al-Zn-Mg合金摩擦系数变化、磨损表面及亚表层的形貌特征和成分特征,研究了试验温度和法向载荷对Al-Zn-Mg合金摩擦行为的影响.结果表明:载荷为5 N时,在25～500℃温度...     

Fe2O3对氧化物弥散强化Fe12CrWTiY合金的显微组织和高温拉伸性能的影响

采用气体雾化Fe-12Cr-2.5W-0.4Ti-0.25Y合金粉末,添加1%(质量分数)的Fe2O3作为携氧剂,制备氧化物弥散强化Fe-12Cr-2.5W-0.4Ti-0.25Y高温合金。测定该合金在室温以及550~850℃的高温抗拉强度,采用X射线衍射仪分析合金的物相组成,通过扫描电镜和透射电镜观察合金的组织和拉伸断口形貌。结果表明,添加Fe2O3后,合金晶粒细化,平均晶粒尺寸由8.6μm减小到7.3μm。基体中第二相除纳米尺寸的Ti2Y2O7外,还形成20~200nm和1~10μm两种尺度的Y3Fe5O12、Cr1.3Fe0.7O3和(Cr0.88Ti0.12)2O3等多种复合氧化物,以及宽度分别为200~300nm和5~30 nm的板条组织,室温、550℃和850℃下的抗拉强度分别为1 257、1 108、和128 MPa,比未添加Fe2O3的合金分别提高50.7%,39%和30.6%。添加Fe2O3增加了氧化物的数量,提高了弥散强化效果,但微米尺度氧化物第二相的膨胀系数与基体不同,在高温下与基体的界面产生分离,优先形成裂纹源,降低高温强化效果。