共查询到18条相似文献,搜索用时 156 毫秒
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夹杂是影响ZM6镁合金铸件力学性能的重要因素。通过拉伸试验测试含有夹杂缺陷ZM6镁合金的力学性能,对试样断口宏观形貌和微观形貌进行观察,测量夹杂物尺寸,定量研究夹杂物的等效直径对抗拉强度和伸长率的影响,建立抗拉强度和伸长率分别与夹杂物等效直径之间的函数关系,并采用ANSYS软件建立含有不同夹杂物尺寸的ZM6镁合金有限模型。结果表明:ZM6合金中的夹杂物主要为氧化镁;等效直径能够很好的表征夹杂物尺寸,随着夹杂物等效直径的增大,抗拉强度和伸长率会随之降低;有限元模拟表明夹杂物和基体界面位置存在明显应力集中,且位于基体较薄界面位置,可较准确预测含不同尺寸夹杂物的合金拉伸性能,拉伸应力应变曲线偏差5%之内,抗拉强度预测误差小于10%。 相似文献
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本文研究了气体保护条件下,常规熔铸的Mg-Gd-Y-Zr合金中夹杂物的形貌、分布及形成原因,并通过计算分析了夹杂物的沉降行为.结果表明,Mg-Gd-Y-Zr合金中有MgO或Y的氧化物为主的球状、簇状、不规则状、线状的复合夹杂物和含熔剂夹杂物,夹杂物的平均尺寸为12.7μm,平均体积分数为0.26%.夹杂物出现的频率随其尺寸增大而急剧减小,尺寸在20μm以下的夹杂物占夹杂物总体积接近85%,尺寸在45μm以下的夹杂物占96%.计算结果表明,夹杂物沉降速率与其尺寸和密度相关;夹杂物密度增大,可使镁合金中夹杂物的最大尺寸减小,计算得到的合金中最大夹杂物的尺寸与实验结果基本一致. 相似文献
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对差压铸造生产的A356铝合金转向节铸件进行了疲劳性能测试、疲劳断口扫描、XRF观察、金相组织观察与夹杂物统计、电解萃取夹杂物、XRD和EDS等试验。结果表明,铸件中夹杂物主要是氧化夹杂物,还包括少量的氮化物、碳化物和金属杂质等,而且铸件上部的夹杂物多于下部,右侧中Al_2O_3和SiO_2夹杂物的含量略高于左侧的铸件。 相似文献
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镁合金熔体净化工艺的研究 总被引:1,自引:0,他引:1
研究了镁合金再生过程中熔体内夹杂物含量、尺寸与静置时间的关系,以及主要合金成分和杂质元素含量的变化规律.应用Stokes公式模拟了夹杂物沉降距离与静置时间的关系,分析了影响夹杂物沉降速度的因素.结果表明:在镁合金废料完全熔解后静置5~10 min,可以将熔体内夹杂物的含量降至0.5%以下,夹杂颗粒尺寸小于0.3 mm.234熔剂的精炼效果好于RJ-1熔剂,经234熔剂精炼后静置8 min,镁合金熔体中的夹杂物含量降至0.02%以下,夹杂颗粒尺寸小于10μm.夹杂物沉降速度与夹杂半径的平方、夹杂密度成正比,与镁合金液粘性系数及镁合金液密度和夹杂密度的比值成反比. 相似文献
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采用电镜和金相等手段,对加稀土氧化物和不加稀土氧化物的堆焊金属中的夹杂物进行了研究,结果表明,稀土氧化物能细化堆焊金属中的夹杂物,减少了尺寸大的夹杂物数量,使其尺寸分布在8μm以下,同时,稀土氧化物能够改善夹杂物的形状,减少了形状系数大的长条状夹杂物数量,使形状系数接近为1的夹杂物较多。稀土氧化物还能变质堆焊金属中夹杂物的属性,可以形成铝、硅、镧的氧化物夹杂和铝、硅、镧的硫氧化物夹杂,并且减少了有害的硫化锰和铝、锰、钛复合夹杂物在堆焊金属中的存在。 相似文献
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In this study, the oxide inclusions contained in the 2205 duplex stainless steel were characterized, and the pitting corrosion initiated at the inclusions was statistically analyzed. The micro-electrochemical behavior was measured by a home-designed capillary microelectrode technique. Results show that three types of oxide inclusions are contained in the steel, namely, Al–Mg–O (inclusion A), Al–Si–Ca–O (inclusion B), and Al–Mg–Si–Ca–O (inclusion C) inclusions. Inclusion A possesses higher electrochemical stability than the steel substrate, and there is no corrosion pit initiated on the inclusion. Inclusions B and C are more electrochemically active than the steel, and pitting corrosion occurs on both inclusions. The α phase has higher electrochemical activity and lower corrosion resistance than the γ phase. Pitting corrosion is more likely to occur at the inclusion/α phase interface, rather than the inclusion/γ phase interface. When the inclusion is located at the α/γ interface, the pit initiation is dominated by the α phase on the coexisting dual phases. 相似文献
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The precipitation behavior of the MnS phase of MnO-SiO2 oxides in Si/Mn deoxidized steels was examined. MnS phase formation in the oxide phase was clearly identified, and the Mn
content in both phases increased with isothermal holding at 1,200°C. With increased cooling rate, both the size of inclusions
and the precipitation ratio of the MnS phase in the oxides decreased. More than 90% of MnO-SiO2 oxides contain MnS phases and MnS precipitation is accompanied by an Mn-depleted zone around the oxides. This zone was created
not just around the MnS, but around the whole oxide inclusion. One can tentatively conclude that the majority of the MnS islands
after isothermal holding are formed by the diffusion of Mn and S from the matrix into the inclusions. 相似文献
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W. M. Wojcik R. M. Raybeck E. J. Paliwoda 《JOM Journal of the Minerals, Metals and Materials Society》1967,19(12):36-40
A new technique, Coulter Counter Particle Size Analysis, has been applied to the study of oxide inclusions in seamless ingots and their effect on defect occurrence in the finished product. The volume of oxide inclusions in representative small steel samples is a measure of hot working quality within ingots and between seamless heats. Furthermore, oxide inclusion distribution by size is a log-normal function indicating that most large and small inclusions have a similar morphology. A series of calculations were made on the number of hot working defects to be expected from the oxide inclusion population of the subject steels. Close agreement between the number of calculated defects and observed defects was obtained. 相似文献
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为研究脱氧方式对船板夹杂物形态和耐蚀性能的影响,采用锆脱氧和铝脱氧,对比两种脱氧条件下钢板晶粒尺寸、夹杂物形态和耐腐蚀性能。结果表明,锆脱氧试验钢夹杂物主要为钙铝酸盐夹杂、球形复合氧化物;其中,大颗粒和长条状MnS夹杂物的密度较低,夹杂物弥散细小,可以阻止晶界迁移带来的晶粒长大,有效细化钢板晶粒尺寸。锆脱氧形成的钢中细小氧化物可以作为MnS异质形核核心,降低了钢基体MnS夹杂微区电化学腐蚀敏感性与扩展速度;这种复合氧化物电化学稳定性好,与铝脱氧方式相比,可以有效提升钢板耐蚀性能。 相似文献
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《工业材料与腐蚀》2020,71(6):869-869
Cover: Three types of oxide inclusions are contained in the steel. Al-Si-Ca-O and Al-Mg-Si-Ca-O inclusions are more electrochemically active than the steel, and pitting corrosion occurs on both inclusions. α phase has a higher electrochemical activity and a lower corrosion resistance than γ phase. Pitting corrosion is more likely to occur at the inclusion/α phase interface, rather than the inclusion/γ phase interface. More detailed information can be found in: Yaohua Zhang, Qian Hu, Mingjie Dai, Feng Huang, Y. Frank Cheng, Jing Liu, Investigation of microelectrochemical activities of oxide inclusions and micro-phases in duplex stainless steel and the implication on pitting corrosion, Materials and Corrosion 2020 , 71, 876. 相似文献
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Impurities such as Fe, Ni and Cu and non-metallic inclusions such as oxides, nitrides, carbides, sulfides and fluorides are
harmful to the quality and various properties of magnesium alloy sheets produced by twin-roll casting. In this study, the
changes of the content of Fe and non-metallic inclusions in AZ31B magnesium alloys with melt temperature and isothermal holding
time were quantitatively evaluated using EPMA and the metallographic method. The Fe content did not increase above the Fe
content in the raw material, which implies that the dissolution of Fe from a steel crucible was suppressed effectively. The
content of non-metallic inclusions, mainly consisting of oxide, fluoride and Fe-rich intermetallic compounds, did not change
remarkably with the melt temperature but it increased with the isothermal holding time due to the continuous oxidation of
the magnesium alloy melt on the melt surface. 相似文献