The present study deals with the effects of both tin (Sn) and graphite (Gr) powders on the cold extrudability of Fe-TiC nanocomposites as lubricant. The production process includes low-energy ball milling, powder meta...The present study deals with the effects of both tin (Sn) and graphite (Gr) powders on the cold extrudability of Fe-TiC nanocomposites as lubricant. The production process includes low-energy ball milling, powder metallurgy and cold direct Extrusion. Due to various factors influencing the extrudability of the Fe-TiC nanocomposites, such as milling time, rate of extrusion, type and content of lubricant and etc, Taguchi robust design method of system optimization was used to determine the approximate contribution percent (% ρ) of each factor. In order to investigation of Fe-TiC properties, samples with best quality of extrusion were analyzed by XRD and SEM investigations. The results indicate that, sitting the atomic layers of Sn lubricant between Fe and TiC particles leads to decreasing the friction. In this case sliding the particles on each other is easier and a part of the load is applied on lubricant. The results of extrusion of samples indicate that using 2% Sn admixed and die wall graphite lubrication can improve cold extrudability of Fe-TiC nanocomposites.展开更多
为探究超声振动对热变形钕铁硼磁体晶粒尺寸和择优取向的影响及其机制,在其热变形过程中施加超声振动,通过SEM图像和Image Pro Plus软件对磁体的晶粒尺寸分布进行分析;通过XRD图谱和SEM晶粒形貌对磁体的晶粒取向度进行分析;并对磁体的...为探究超声振动对热变形钕铁硼磁体晶粒尺寸和择优取向的影响及其机制,在其热变形过程中施加超声振动,通过SEM图像和Image Pro Plus软件对磁体的晶粒尺寸分布进行分析;通过XRD图谱和SEM晶粒形貌对磁体的晶粒取向度进行分析;并对磁体的应变激活能和磁性能进行分析。结果表明,超声振动对热变形钕铁硼晶粒存在细化作用,细晶区的平均晶粒尺寸相较于常规热变形磁体减小约50%,且提高超声功率密度可使晶粒细化作用明显增强。超声振动促进了主磁相晶粒的转动,更多晶粒c轴转至压力方向,使整体择优取向得到改善。此外,超声振动促进了磁体径向方向晶粒取向的均匀分布,减小了热变形磁体剩磁沿径向方向的差异。展开更多
以TiFe粉和碳的前驱体(石油沥青)为原料,通过碳化制备Ti Fe C系反应喷涂复合粉末,并通过普通火焰喷涂技术成功制备了TiC/Fe金属陶瓷复合涂层;采用XRD、SEM和EDS对喷涂粉末和涂层的成分、组织结构进行了分析,同时对涂层耐磨性能进行了对...以TiFe粉和碳的前驱体(石油沥青)为原料,通过碳化制备Ti Fe C系反应喷涂复合粉末,并通过普通火焰喷涂技术成功制备了TiC/Fe金属陶瓷复合涂层;采用XRD、SEM和EDS对喷涂粉末和涂层的成分、组织结构进行了分析,同时对涂层耐磨性能进行了对比研究。结果表明:采用前驱体碳化复合技术制备的Ti Fe C系复合喷涂粉末粒度均匀、无有害相生成;喷涂所得到的TiC/Fe金属陶瓷复合涂层由片状的铁基体和弥散分布的TiC颗粒组成;TiC颗粒大致呈球形,粒度一般在0.5μm以下;相同条件下所获涂层的磨损体积大约是常规火焰喷涂Ni60涂层的1/5。展开更多
文摘The present study deals with the effects of both tin (Sn) and graphite (Gr) powders on the cold extrudability of Fe-TiC nanocomposites as lubricant. The production process includes low-energy ball milling, powder metallurgy and cold direct Extrusion. Due to various factors influencing the extrudability of the Fe-TiC nanocomposites, such as milling time, rate of extrusion, type and content of lubricant and etc, Taguchi robust design method of system optimization was used to determine the approximate contribution percent (% ρ) of each factor. In order to investigation of Fe-TiC properties, samples with best quality of extrusion were analyzed by XRD and SEM investigations. The results indicate that, sitting the atomic layers of Sn lubricant between Fe and TiC particles leads to decreasing the friction. In this case sliding the particles on each other is easier and a part of the load is applied on lubricant. The results of extrusion of samples indicate that using 2% Sn admixed and die wall graphite lubrication can improve cold extrudability of Fe-TiC nanocomposites.
文摘为探究超声振动对热变形钕铁硼磁体晶粒尺寸和择优取向的影响及其机制,在其热变形过程中施加超声振动,通过SEM图像和Image Pro Plus软件对磁体的晶粒尺寸分布进行分析;通过XRD图谱和SEM晶粒形貌对磁体的晶粒取向度进行分析;并对磁体的应变激活能和磁性能进行分析。结果表明,超声振动对热变形钕铁硼晶粒存在细化作用,细晶区的平均晶粒尺寸相较于常规热变形磁体减小约50%,且提高超声功率密度可使晶粒细化作用明显增强。超声振动促进了主磁相晶粒的转动,更多晶粒c轴转至压力方向,使整体择优取向得到改善。此外,超声振动促进了磁体径向方向晶粒取向的均匀分布,减小了热变形磁体剩磁沿径向方向的差异。
文摘以TiFe粉和碳的前驱体(石油沥青)为原料,通过碳化制备Ti Fe C系反应喷涂复合粉末,并通过普通火焰喷涂技术成功制备了TiC/Fe金属陶瓷复合涂层;采用XRD、SEM和EDS对喷涂粉末和涂层的成分、组织结构进行了分析,同时对涂层耐磨性能进行了对比研究。结果表明:采用前驱体碳化复合技术制备的Ti Fe C系复合喷涂粉末粒度均匀、无有害相生成;喷涂所得到的TiC/Fe金属陶瓷复合涂层由片状的铁基体和弥散分布的TiC颗粒组成;TiC颗粒大致呈球形,粒度一般在0.5μm以下;相同条件下所获涂层的磨损体积大约是常规火焰喷涂Ni60涂层的1/5。
