在30kW级直流电弧等离子体喷射化学气相沉积(DC Arc P lasm a Jet CVD)设备上,采用Ar-H2-CH4混合气体,通过调节甲烷浓度以及控制其他沉积参数,在Mo衬底上沉积出微/纳米复合自支撑金刚石膜。实验表明,当微米金刚石膜层沉积结束后,在随后...在30kW级直流电弧等离子体喷射化学气相沉积(DC Arc P lasm a Jet CVD)设备上,采用Ar-H2-CH4混合气体,通过调节甲烷浓度以及控制其他沉积参数,在Mo衬底上沉积出微/纳米复合自支撑金刚石膜。实验表明,当微米金刚石膜层沉积结束后,在随后的沉积中,随着甲烷浓度的增加,金刚石膜表面的晶粒大小是逐渐减小的。当甲烷浓度达到20%以上时,金刚石膜生长面晶粒呈现菜花状的小晶团,膜体侧面已经没有了粗大的柱状晶,而是呈现出光滑的断口,对该层进行拉曼谱分析显示,位于1145 cm-1附近有一定强度的散射峰出现。这说明所沉积的晶粒全部变为纳米级尺寸。展开更多
An attempt is made to develop the tools that are capable enough to withstand the shear, impact and thermal forces that occur during friction stir welding of stainless steels. The atmospheric plasma spray and plasma tr...An attempt is made to develop the tools that are capable enough to withstand the shear, impact and thermal forces that occur during friction stir welding of stainless steels. The atmospheric plasma spray and plasma transferred arc hardfacing processes are employed to deposit refractory ceramic based composite coatings on the Inconel 738 alloy. Five different combinations of self-fluxing alloy powder and 60% ceramic reinforcement particulate mixtures are used for coating. The best friction stir welding tool selected based on tool wear analysis is used to fabricate the austenitic stainless steel joints.展开更多
采用等离子填丝焊工艺对轨道车辆用2 mm厚的X2Cr Ni N18-7不锈钢薄板进行对接焊接试验,通过正交试验对焊接电流、焊接速度、送丝速度和离子气流量参数进行了优化,并对最佳工艺参数下的焊接接头质量进行了焊接工艺评定。结果表明:使用Pla...采用等离子填丝焊工艺对轨道车辆用2 mm厚的X2Cr Ni N18-7不锈钢薄板进行对接焊接试验,通过正交试验对焊接电流、焊接速度、送丝速度和离子气流量参数进行了优化,并对最佳工艺参数下的焊接接头质量进行了焊接工艺评定。结果表明:使用Plasmatron等离子焊机成功实现了X2Cr Ni N18-7不锈钢薄板等离子填丝对接焊,优化的焊接工艺参数为焊接电流160 A,焊接速度0.25 m/min,送丝速度3.0 m/min,离子气流量5 L/min;焊缝成形良好,背面全焊透,经X射线探伤无未焊透、未熔合和裂纹等缺陷;焊接接头的综合力学性能良好,焊接接头的抗拉强度平均值为636.57 MPa,焊接接头强度系数为92.28%;180°横向正弯试验结果显示,试样正反两面均无裂纹;当疲劳测试加载循环次数为1.0×107次时,焊接接头的疲劳极限为270 MPa。展开更多
文摘在30kW级直流电弧等离子体喷射化学气相沉积(DC Arc P lasm a Jet CVD)设备上,采用Ar-H2-CH4混合气体,通过调节甲烷浓度以及控制其他沉积参数,在Mo衬底上沉积出微/纳米复合自支撑金刚石膜。实验表明,当微米金刚石膜层沉积结束后,在随后的沉积中,随着甲烷浓度的增加,金刚石膜表面的晶粒大小是逐渐减小的。当甲烷浓度达到20%以上时,金刚石膜生长面晶粒呈现菜花状的小晶团,膜体侧面已经没有了粗大的柱状晶,而是呈现出光滑的断口,对该层进行拉曼谱分析显示,位于1145 cm-1附近有一定强度的散射峰出现。这说明所沉积的晶粒全部变为纳米级尺寸。
基金the Department of Science and Technology (DST), Government of India for the financial support through Fast Track Scheme for Young Scientists R&D project (SR/FTP/ETA043/2009) to carry out this investigation
文摘An attempt is made to develop the tools that are capable enough to withstand the shear, impact and thermal forces that occur during friction stir welding of stainless steels. The atmospheric plasma spray and plasma transferred arc hardfacing processes are employed to deposit refractory ceramic based composite coatings on the Inconel 738 alloy. Five different combinations of self-fluxing alloy powder and 60% ceramic reinforcement particulate mixtures are used for coating. The best friction stir welding tool selected based on tool wear analysis is used to fabricate the austenitic stainless steel joints.
