Tungsten, molybdenum and cobalt were co-diffused into the surface of ingot, 20 steel, 45 steel and T8 steel by a double glow plasma surface alloying technique. Surface alloyed layers formed on ingot and 20 steel are c...Tungsten, molybdenum and cobalt were co-diffused into the surface of ingot, 20 steel, 45 steel and T8 steel by a double glow plasma surface alloying technique. Surface alloyed layers formed on ingot and 20 steel are composed of -Fe +(Fe,Co)7(W,Mo)6, which possess the same strong age-hardening ability as the metallurgical age-hardened high speed steel, the maximum hardness can reach 1100 HV0.o25 after ageing treatment. Surface alloyed layers formed on 45 steel and T8 steel are composed of M6C, hardness of which are over 1100-1400 HV0.o25- Alloyed layers formed on ingot and 20 steel possess good toughness. Alloyed layer of carbide type exhibits slightly brittleness.展开更多
W/Cu Functionally Graded Materials (FGM) was designed not only for reducing the thermal stress caused by the mismatch of thermal expansion coefficients, but also for combining the features of W, Mo - high plasma-erosi...W/Cu Functionally Graded Materials (FGM) was designed not only for reducing the thermal stress caused by the mismatch of thermal expansion coefficients, but also for combining the features of W, Mo - high plasma-erosion resistance and the advantages of Cu - high heat conductivity and ductility. Four different fabrication processes for W/Cu or Mo/Cu, including hot-pressing, Cu infiltration of sintered porosity-graded W skeleton, spark plasma sintering and plasma spraying, were investigated and compared. It was foundthat the hot-pressing process is difficult to keep the designed composition gradient, while the other three processes are successful in making W/Cu or Mo/Cu FGM. Meanwhile, microstructures and composition gradients are analyzed with SEM and EDAX.展开更多
In order to prepare heatresistant inner layer of hot-forging die, plasma spraying, plasma re- melting and plasma spray welding were adopted. Cr3C2 coatings of Ni-Based were prepared respectively with 10%, 20% and 30% ...In order to prepare heatresistant inner layer of hot-forging die, plasma spraying, plasma re- melting and plasma spray welding were adopted. Cr3C2 coatings of Ni-Based were prepared respectively with 10%, 20% and 30% Cr3C2 powder and W6Mo5Cr4V2 substrate. The coating microstructure analysis, the micro-hardness test, and the measurement of thermal parameters of coating were conducted. The experimental results show that the coating has the better thermo-physical property by using plasma spray welding method with the powder ratio of 90% Ni60 and 10% Cr3C2, and by this way the micro-hardness of coating can achieve 1100 HV.展开更多
采用双层辉光离子渗金属技术,在工业纯铁和20钢表面进行W、Mo、Co多元共渗,形成Fe W Mo Co型渗镀复合层.对渗镀层进行了金相组织观察、成分及硬度测量,重点研究了镀层的相组成及镀层与基体间的结合强度.结果表明:纯铁和20钢表面镀层以...采用双层辉光离子渗金属技术,在工业纯铁和20钢表面进行W、Mo、Co多元共渗,形成Fe W Mo Co型渗镀复合层.对渗镀层进行了金相组织观察、成分及硬度测量,重点研究了镀层的相组成及镀层与基体间的结合强度.结果表明:纯铁和20钢表面镀层以金属钨、钼为基体,其上分布大量μ相,并有少量Laves相;镀层硬度高达1000～1400HV,固溶和时效处理对硬度提高影响不大;纯铁表面镀层在渗金属、固溶、时效状态下,持续加载100N未发生镀层剥落现象;20钢表面镀层经固溶处理后,所加载荷在100N内未发生剥落现象,但在渗金属及时效态,当载荷加至80N时,镀层开始剥落.展开更多
采用超音速等离子喷涂技术在45Cr Ni MoVA钢表面制备Mo-W合金涂层,对涂层进行了从400～1000℃不同温度条件下的热处理,对不同处理状态下的涂层进行了电弧烧蚀试验。利用场发射扫描显微镜(SEM)、电子能谱仪(EDS)分析涂层组织和成分,利用...采用超音速等离子喷涂技术在45Cr Ni MoVA钢表面制备Mo-W合金涂层,对涂层进行了从400～1000℃不同温度条件下的热处理,对不同处理状态下的涂层进行了电弧烧蚀试验。利用场发射扫描显微镜(SEM)、电子能谱仪(EDS)分析涂层组织和成分,利用维氏显微硬度计测试硬度,利用四探针电阻仪测定涂层电阻率。结果表明:热处理工艺可以改变合金元素的固溶度,但并不能明显消除喷涂层中孔隙等宏观缺陷;随着热处理温度升高,Mo-W喷涂层的显微硬度由563.2 HV0.1下降为460.6 HV0.1(1000℃),涂层的导电率呈现缓慢增加趋势;热处理温度为1000℃时涂层导电率最高,为6.42%IACS。在1000℃以下进行热处理,Mo-W涂层的耐电弧烧蚀性能有所提升。展开更多
基金supported by the Natural Science Foundation of Shanxi Province under Contract Number 20021054the Youth Science Foundation of Taiyuan University of Technology under Contract Number 190-100003.
文摘Tungsten, molybdenum and cobalt were co-diffused into the surface of ingot, 20 steel, 45 steel and T8 steel by a double glow plasma surface alloying technique. Surface alloyed layers formed on ingot and 20 steel are composed of -Fe +(Fe,Co)7(W,Mo)6, which possess the same strong age-hardening ability as the metallurgical age-hardened high speed steel, the maximum hardness can reach 1100 HV0.o25 after ageing treatment. Surface alloyed layers formed on 45 steel and T8 steel are composed of M6C, hardness of which are over 1100-1400 HV0.o25- Alloyed layers formed on ingot and 20 steel possess good toughness. Alloyed layer of carbide type exhibits slightly brittleness.
文摘W/Cu Functionally Graded Materials (FGM) was designed not only for reducing the thermal stress caused by the mismatch of thermal expansion coefficients, but also for combining the features of W, Mo - high plasma-erosion resistance and the advantages of Cu - high heat conductivity and ductility. Four different fabrication processes for W/Cu or Mo/Cu, including hot-pressing, Cu infiltration of sintered porosity-graded W skeleton, spark plasma sintering and plasma spraying, were investigated and compared. It was foundthat the hot-pressing process is difficult to keep the designed composition gradient, while the other three processes are successful in making W/Cu or Mo/Cu FGM. Meanwhile, microstructures and composition gradients are analyzed with SEM and EDAX.
文摘In order to prepare heatresistant inner layer of hot-forging die, plasma spraying, plasma re- melting and plasma spray welding were adopted. Cr3C2 coatings of Ni-Based were prepared respectively with 10%, 20% and 30% Cr3C2 powder and W6Mo5Cr4V2 substrate. The coating microstructure analysis, the micro-hardness test, and the measurement of thermal parameters of coating were conducted. The experimental results show that the coating has the better thermo-physical property by using plasma spray welding method with the powder ratio of 90% Ni60 and 10% Cr3C2, and by this way the micro-hardness of coating can achieve 1100 HV.
文摘采用双层辉光离子渗金属技术,在工业纯铁和20钢表面进行W、Mo、Co多元共渗,形成Fe W Mo Co型渗镀复合层.对渗镀层进行了金相组织观察、成分及硬度测量,重点研究了镀层的相组成及镀层与基体间的结合强度.结果表明:纯铁和20钢表面镀层以金属钨、钼为基体,其上分布大量μ相,并有少量Laves相;镀层硬度高达1000～1400HV,固溶和时效处理对硬度提高影响不大;纯铁表面镀层在渗金属、固溶、时效状态下,持续加载100N未发生镀层剥落现象;20钢表面镀层经固溶处理后,所加载荷在100N内未发生剥落现象,但在渗金属及时效态,当载荷加至80N时,镀层开始剥落.
文摘采用超音速等离子喷涂技术在45Cr Ni MoVA钢表面制备Mo-W合金涂层,对涂层进行了从400～1000℃不同温度条件下的热处理,对不同处理状态下的涂层进行了电弧烧蚀试验。利用场发射扫描显微镜(SEM)、电子能谱仪(EDS)分析涂层组织和成分,利用维氏显微硬度计测试硬度,利用四探针电阻仪测定涂层电阻率。结果表明:热处理工艺可以改变合金元素的固溶度,但并不能明显消除喷涂层中孔隙等宏观缺陷;随着热处理温度升高,Mo-W喷涂层的显微硬度由563.2 HV0.1下降为460.6 HV0.1(1000℃),涂层的导电率呈现缓慢增加趋势;热处理温度为1000℃时涂层导电率最高,为6.42%IACS。在1000℃以下进行热处理,Mo-W涂层的耐电弧烧蚀性能有所提升。
