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以TiCp粉末和水雾化Cr15高铬铸铁粉末为原料,采用粉末冶金液相烧结技术制备TiCp增强高铬铸铁复合材料。研究了TiCp含量对高铬铸铁的物相组成、显微组织和力学性能的影响。研究结果表明,全致密的TiCp增强高铬铸铁基体复合材料的构成相为TiC、M7C3型碳化物、马氏体和少量奥氏体;随着TiCp添加量增大,金属基体逐步呈孤岛状,并在其中析出越来越多的M7C3型碳化物,同时TiCp逐步呈连续网状分布;同时,其硬度稳步提升,而抗弯强度和冲击韧性降低。当TiCp添加量为20wt%时烧结态复合材料具有最佳综合力学性能。此时硬度为HRC 66.8 ,冲击韧性为6.86 J/cm2,抗弯强度为1 343.10 MPa。当TiCp添加量为25wt%时硬度达到最大值HRC 67.20 。 相似文献
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摩擦诱发高铬铸铁相变的透射电镜研究 总被引:2,自引:0,他引:2
利用透射电子显微镜研究了高铬铸铁在摩擦过程中的显微组织变化。结果表明:奥氏体基体在摩擦应力的作用下发生相变。摩擦表面形成α‘M。次表层形成γ与α’M共存区;γ与.ε共存区;γ位错丛聚区。 相似文献
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目前,有关淬火后回火温度对Cr26高铬铸铁组织及性能的研究报道不多。为此,采用XRD、OM、SEM、TEM和电子拉力试验机和洛式硬度计,研究了回火温度对Cr26高铬铸铁调质处理前后的显微组织和力学性能的影响。结果表明:调质处理前Cr26高铬铸铁中碳化物类型有M_7C_3、M_(23)C_6和M_3C_2;调质处理后Cr26高铬铸铁的显微组织得到明显改善,基体上弥散分布着细小的碳化物;抗拉强度和硬度值随回火温度的增加而降低,延伸率有所提高;回火温度为560℃左右时,抗拉强度、延伸率和硬度值分别为1 294 MPa、8.02%和38.6 HRC,有良好的力学性能。 相似文献
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采用高能球磨和真空烧结的方法制备TiC增强高铬铸铁(HCCI)基复合材料。利用SEM,DSC等方法对不同球磨时间的粉末进行分析,研究不同烧结温度对高铬铸铁基复合材料的显微组织、硬度及密度的影响,比较相同工艺下复合材料与高铬铸铁材料的耐磨性。结果表明:球磨12 h后的粉末颗粒大小趋于稳定,粉末活性提高,烧结性能改善,烧结试样中TiC均匀地分布在基体中。随着烧结温度的升高,复合材料内部晶粒逐渐长大,密度和硬度逐渐提高。在1280℃超固相线液相烧结的条件下烧结2 h后,致密度达94.17%,硬度和抗弯强度分别为49.2HRC和980 MPa。在销盘磨损实验中复合材料的耐磨性为单一高铬铸铁材料的1.52倍,磨损机制为磨粒磨损+轻微氧化磨损。 相似文献
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本文采用稀土变质荆对高铬铸铁进行变质处理,通过OM和SEM测试观察高铬铸铁变质处理前后及热处理前后的形貌及微观组织,并通过硬度、冲击韧性及磨损量测试研究变质和热处理对其力学性能的影响。结果表明:高铬铸铁在经过稀土变质处理后组织细化,网状碳化物破碎成孤立块状,硬度、冲击韧性及耐磨性提高;经过950℃-1000℃正火处理后,碳化物进一步破碎,在奥氏体基体上析出弥散的二次碳化物,进一步提高了高铬铸铁的硬度、韧性和耐磨性能。 相似文献
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利用锻造方法并结合锻后适当的热处理工艺可大幅度提高铬合金白口铸铁的冲击韧性.采用热望性镦粗试验方法,对不同碳含量中铬合金白口铸铁的热塑性、碳对中铬白口铸铁热塑性的影响规律进行了研究,分析了不同热处理工艺对其锻后组织和性能的影响,并提出了可明显提高锻造中铬合金白口铸铁抗冲击磨损性能的热处理工艺参数.研究表明:含碳量为1.85%-2.59%的中铬合金自口铸铁在850-1130℃的温度范围内,具有良好的塑性变形能力,且随碳含量的增加,中铬白口铸铁的热塑性下降,其主要原因是碳含量不同所引起的组织中共晶碳化物的数量的改变所致. 相似文献
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16Cr2Mo1Cu高铬铸铁在亚临界处理中硬化行为研究 总被引:2,自引:0,他引:2
研究了亚临界处理对16Cr2Mo1Cu高铬铸铁的组织转变和性能的影响,并利用X射线衍射分析、磁性法和硬度测定法分析了硬化机制.研究表明:16Cr2Mo1Cu高铬铸铁的铸态组织由残余奥氏体、马氏体和M7C3型共晶碳化物组成,其相对含量分别为77.0%,7.2%和15.8%;在亚临界处理过程中,基体组织中的残余奥氏体析出二次碳化物并在冷却过程中转变为马氏体,使该合金在560~600℃的亚临界处理过程中出现二次硬化;在适当的处理温度和保温时间下,16Cr2Mo1Cu高铬铸铁可得到最高的硬度. 相似文献
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It is attempted to enhance the impact toughness of industrially used high chromium white cast iron (WCI) without sacrificing wear resistance. The microstructure is engineered by cyclic annealing to obtain features such as duplex grain matrix, where austenite envelops ferrite grain, refined M7C3 carbide. The newly cast and heat-treated alloy shows remarkable impact toughness i.e. 13J with improved wear resistance. The fracture micro-mechanism is studied through extensive scanning electron microscopy and it is ascertained that enhanced impact toughness results from crack arrest at duplex grain boundaries. A few other toughness enhancing features are also discussed. The results are compared with standard ASTM grade Class-III high chromium WCI and are found to be encouraging. 相似文献
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To attain a wear‐resistant material compatible with high hardness and high toughness, Hadfield steel matrix was reinforced by oriented high chromium cast iron bars, through inserting high chromium alloys flux‐cored welding wires into Hadfield steel melt at 1500 ± 10 °C. The obtained composites were investigated by XRD, SEM, micro‐hardness, three‐body abrasion wear and impact toughness testers. The results show that the alloy powders inside the flux‐cored welding wires can be melted by the heat capacity of Hadfield steel melt and in situ solidified into high chromium cast iron bar reinforcements tightly embedded in the matrix. The micro‐hardness of reinforcements of the water‐quenched composite is about four times higher than that of the matrix. The impact toughness of the water‐quenched composite is higher than that of the as‐cast composite and lower than that of Hadfield steel, and its fracture mechanism is very complicated and refers to brittle and ductile mixture fracture mode. The excellent impact toughness and better wear resistance of the water‐quenched composite are attributed to combine fully the advantages and avoid the drawbacks of both Hadfield steel and high chromium cast iron. Additionally, in industrial application, the pulverizer plate produced by this composite, has also better wear resistance compared to the reference Hadfield steel pulverizer plate. 相似文献
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Zhongli Liu Yanxiang Li Xiang Chen Kaihua Hu 《Materials Science and Engineering: A》2008,486(1-2):112-116
In this paper, high boron white cast iron, a new kind of wear-resistant white cast iron was developed, and its microstructure and mechanical properties were studied. The results indicate that the high boron white cast iron comprises a dendritic matrix and an interdendritic eutectic boride in as-cast condition. The distribution of eutectic boride with a chemical formula of M2B (M represents Cr, Fe or Mn) and with a microhardness of HV2010 is much like that of carbide in high chromium white cast iron. The matrix includes martensite and a small amount of pearlite. After quenching in air, the matrix changes to martensite, but the morphology of boride remains almost unchanged. In the course of austenitizing, a secondary precipitation with the size of about 1 μm appears, but when tempered at different temperature, another secondary precipitation with the size of several tens of nanometers is found. Both secondary precipitations, which all forms by means of equilibrium segregation of boron, have a chemical formula of M23(C,B)6. Compared with high chromium white cast iron, the hardness of high boron white cast iron is almost similar, but the toughness is increased a lot, which attributes to the change of matrix from high carbon martensite in the high chromium white cast iron to low carbon martensite in the high boron white cast iron. Moreover, the high boron white cast iron has a good hardenability. 相似文献
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为获得兼具较高强度和良好低温冲击韧性的球墨铸铁铸件,向球墨铸铁中加入质量分数约0.5%的Ni进行合金化,并对其进行中温奥氏体化(880℃+3 h)和低温退火(720℃+4 h)处理.采用光学显微镜(OM)、扫描电子显微镜(SEM)对铸态和热处理态试样的显微组织和冲击断口形貌进行分析;利用万能试验机、布氏硬度计和摆锤式冲击试验机等对铸态和热处理态试样进行了室温拉伸、硬度检测、低温冲击等力学性能测试.结果表明:铸态球墨铸铁的微观组织由珠光体、铁素体和球状石墨及少量的渗碳体组成,其强度、硬度偏高,塑性、韧性较差;热处理态试样中的珠光体向铁素体转变后为铁素体和球状石墨,试样强度、硬度有所降低,塑性、韧性得到明显的改善;铸态试样呈现典型的脆性断裂特征,热处理态试样冲击断口处存在少量韧窝,断裂模式以解理断裂为主,伴有少量塑性变形的韧脆混合断裂,且在-40℃冲击功达到12.4 J;比较铸态与热处理态的冲击断口形貌可知,试样断裂方式由脆性断裂转变为韧脆混合断裂. 相似文献
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为提高低合金高强铸钢(HSLA)的综合力学性能,满足恶劣环境下的使用要求.采用光学显微镜、扫描电镜、透射电镜、冲击试验机、万能材料试验机研究了3种不同冷速及高温回火对HSLA铸钢组织与力学性能的影响.结果表明:随冷速增加,淬火组织发生由多边形铁素体+针状铁素体+粒状贝氏体→粒状贝氏体+板条贝氏体→准上贝氏体+板条马氏体的演变.冷速为1℃/s的空冷样,具有最高的塑韧性;冷速最大的水冷样,其强度、硬度最高.冷却样经580℃回火,其晶界、板条界均有粒状、短棒状的纳米第二相析出,EDS分析表明,100~200 nm的析出相为合金渗碳体(M3C),而50 nm以内的析出相为(V,Ti)(C,N).空冷样回火后有较高强度、最高的塑韧性;油冷、水冷样回火后,Re提高,Rm略有下降,AkU降低与高温回火脆性的发生有关,但-40℃的AkU仍有60、40 J,具有较好的低温冲击韧性.可见,试验HSLA铸钢表现出良好的综合力学性能,能满足在恶劣环境下的使用要求. 相似文献
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稀土变质及热处理对高碳铬铸钢力学性能影响 总被引:1,自引:0,他引:1
研究了稀土变质与热处理对高碳铬铸钢力学性能的影响.采用金相显微镜、扫描电子显微镜观察了试样碳化物的形貌、冲击断口及磨面特征,用公式s=20.3 z/P2计算了碳化物的形状因子;采用冲击试验机、万能试验机等测试了试样的冲击韧性、抗弯强度、挠度;用动载磨损试验机对试样进行了磨损试验.结果表明:高碳铬铸钢经0.22%稀土变质后再经960℃×3 h正火,其冲击韧性提高180%,,抗磨性提高20%,强度提高76%,塑性也有所提高.其主要原因在于稀土变质及热处理使高碳铬铸钢组织中连续网状的共晶碳化物转变为孤立的块状、碳化物的形状因子增大以及粒状碳化物的析出所致. 相似文献