共查询到18条相似文献,搜索用时 78 毫秒
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研究了高硼中碳合金钢凝固过程中施加电脉冲的凝固组织.结果表明,经过电脉冲处理,高硼中碳合金钢晶粒得到细化,晶粒形状趋于圆整,分布更加均匀,马氏体片层间距减小,硬质相体积分数由未经电脉冲处理时的10.6%降低到8.3%,基体中W、Cr、Mo、V等合金元素含量上升,基体硬度由HV664提高到HV730,网状硬质相产生断网现象,并且有孤立球化趋势.分析认为,以上是电脉冲的焦耳热效应、电磁力作用、电迁移效应共同作用的结果. 相似文献
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在测试了高硼高速钢轧辊材料临界点和等温转变曲线(TTT)的基础上,借助金相显微镜、扫描电镜、X衍射分析、拉伸试验、冲击试验和硬度试验等手段,研究了淬火处理对高硼高速钢轧辊材料组织与性能的影响.结果表明,高硼高速钢轧辊材料具有很好的淬透性,淬火后易获得高硬度的马氏体组织,且碳硼化合物呈孤立分布.淬火温度超过1050℃后,残留奥氏体增多,硬度反而下降.随着淬火温度升高,高硼高速钢的抗拉强度和冲击韧性提高,超过1050℃,抗拉强度的变化不明显.高硼高速钢在1050℃左右淬火,具有优良的综合性能. 相似文献
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借助光学显微镜、扫描电镜和X射线衍射仪研究少量铈对高硼高速钢微观组织和力学性能的影响。结果表明:少量铈的添加能显著提高高硼高速钢的冲击韧性和磨损性能,其冲击韧性值(ak)由6.7 J/cm2增加到14.3 J/cm2,少量铈的存在使高硼高速钢中鱼骨状硼碳化物基本消失,大部分羽毛状硼碳化物熔断,粒状硼碳化物增多,硼碳化物分布更加均匀,初生奥氏体晶粒明显细化。 相似文献
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在普通高速钢材料中,加入适量硼来取代普通高速钢中价格昂贵的合金元素,设计了一种新型的高硼高速钢材料。研究了淬火温度对0.4%~0.5%C和1.0%~1.5%B的高硼高速钢显微组织的影响。结果表明,高硼高速钢的铸态组织由铁素体、珠光体和少量马氏体以及硼碳化合物组成,硼碳化合物由M23(B,C)6、(W,Mo)2(B,C),M3(B1.5,C0.5)和M(B0.7,C0.3)组成,呈网状和鱼骨状沿晶界分布。淬火处理后,基体组织转变成板条马氏体,含有4%残留奥氏体,硼碳化合物的类型没有发生变化,但数量减少。在950~1100℃内淬火,硼碳化合物局部发生溶解,出现断网现象;随着淬火温度的升高,断网现象越来越明显,从而减轻了对基体的割裂作用。 相似文献
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添加硼对铸造Ti-46.5Al-8Nb合金组织和性能的影响 总被引:1,自引:0,他引:1
全片层Ti-46.5Al-8Nb合金中添加硼(≤0.7%,原子分数)的显微组织观察表明,细化组织的临界硼含量约为0.5%(原子分数).细化机制与凝固前沿硼产生了附加的成分过冷和硼化物钉扎晶界双重机制有关.由于硼减小了片层形成所需要的过冷度,片层间距随硼含量的增加而增加,片层间距λ与晶粒尺寸d-1/2符合线性关系.添加硼的Ti-46.5Al-8Nb合金的α2相体积分数越高,硬度也越高.合金的断裂强度和延伸率随硼含量增加而增加.室温断裂强度与晶粒尺寸符合Hall-Petch关系. 相似文献
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Effect of homogenization temperature on microstructure and mechanical properties of low-carbon high-boron cast steel 总被引:1,自引:0,他引:1
Hanguang Fu Xuding Song Yongping Lei Zhiqiang Jiang Jun Yang Jinhua Wang Jiandong Xing 《Metals and Materials International》2009,15(3):345-352
The effects of quenching treatment on the microstructure, hardness, impact toughness, and wear resistance of low-carbon high-boron
cast steel (LCHBS) containing 0.15–0.3 %C, 1.4–1.8 %B, 0.3–0.8 %Si, 0.8–1.2 %Mn, 0.5–0.8%Cr, 0.3–0.6%Ni, and 0.3–0.6%Mo have
been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM),
and via an electron probe microanalyzer (EPMA), X-ray diffraction (XRD) analysis, impact tester, hardness tester, and wear
tester. The as-cast matrix of LCHBS consists of pearlite and ferrite. There is 8–10 vol.% Fe2(B, C) type borocarbides in the matrix. The micro-hardness of Fe2(B, C) is 1430–1480 Hv. Fe2(B, C) shows no obvious change and the matrix completely transforms into lath martensite upon quenching at 900 °C to 1100
°C. The microhardness of the matrix and the macrohardness of the LCHBS sample show a slight increase with an increase of homogenization
temperature. When the homogenization temperature exceeds 1050 °C, no distinct change in the hardness is observed. The change
of homogenization temperature has no apparent effect on the impact toughness of LCHBS. The mass losses of LCHBS increase distinctly
when the wear load increases. The homogenization temperature is less than 1000 °C and the wear rate of LCHBS decreases with
an increase of temperature. The wear rate does not display any obvious change after exceeding a homogenization temperature
of 1000 °C. 相似文献
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In this paper, a comparison study was carried out to investigate the influence of carbon content on the microstructure, hardness, and impact toughness of water-quenched Mn13Cr2 and Mn18Cr2 cast steels. The study results indicate that both steels' water-quenched microstructures are composed of austenite and a small amount of carbide. The study also found that, when the carbon contents are the same, there is less carbide in Mn18Cr2 steel than in Mn13Cr2 steel. Therefore, the hardness of Mn18Cr2 steel is lower than that of Mn13Cr2 steel but the impact toughness of Mn18Cr2 steel is higher than that of Mn13Cr2 steel. With increasing the carbon content, the hardness increases and the impact toughness decreases in these two kinds of steels, and the impact toughness of Mn18Cr2 steel substantially exceeds that of Mn13Cr2 steel. Therefore, the water-quenched Mn18Cr2 steel with high carbon content could be applied to relatively high impact abrasive working conditions, while the as-cast Mn18Cr2 steel could be only used under working conditions of relatively low impact abrasive load due to lower impact toughness. 相似文献
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本文利用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)、维氏硬度仪和电子拉伸试验机等分析测试方法,系统地研究了Fe元素含量变化对Ti-xFe-B(x=1 ~ 5 wt%)合金铸态组织演变及力学性能的影响。研究表明:在Fe含量1 ~ 3 wt%时,合金组织由片层状α相和少量β相组成,当Fe含量增加至4 ~ 5 wt%时,合金组织的组成中β相增加显著,同时随着Fe含量从1 wt%增至5 wt%,析出化合物中Fe元素含量上升,α相晶粒尺寸下降了56.5%;随着Fe含量增加,合金力学性能改变显著,维氏硬度增加了45.7%,抗拉强度由502 MPa增加至834 MPa,但合金塑性下降明显,断面收缩率从30.4%下降至9.5%,断裂伸长率由19.4%下降到7.9%。结果显示,当Fe含量在3 ~ 4 wt%时,合金可以达到强度和塑性的最佳匹配,具有更大的开发潜力。 相似文献
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针对新型钢铁材料焊缝熔敷金属的韧化问题,采用直接氧化物合金化这一新型方法,通过焊接材料实现了纳米氧化物颗粒向液态熔池中的过渡,研究了纳米氧化物对低合金高强钢焊缝熔敷金属组织性能的影响. 结果表明,纳米Al2O3,TiO2和稀土氧化物的添加使焊缝中生成了大量弥散分布、尺寸为0.2~0.8 μm的细小球形复合夹杂物,有效提高了针状铁素体的形核能力,形成了大量板条束尺寸约1~2 μm、且均匀分布的针状铁素体. 纳米氧化物的添加使熔敷金属的冲击韧性显著提高,尤其是添加二氧化钛和稀土氧化物的焊缝,其-20℃冲击韧性达到了150 J/cm2以上,比无氧化物添加的焊缝冲击韧性提高67%. 相似文献