旋锻法制备高掺杂ThO_2纳米颗粒的W热阴极材料的结构与性能

采用热旋锻工艺制备了纳米复合W-4.5%ThO2阴极材料,为了对其抗烧蚀性能进行研究,在氩弧焊机(GTA)上与商用W-2%ThO2和W-4.5%ThO2电极进行了比较试验。结果表明,这种新型电极的密度接近于全致密,其组织结构与目前工艺生产的商用电极完全不同,粒径小于200 nm的ThO2颗粒弥散分布于钨基体晶粒内。纳米复合W-4.5%ThO2阴极材料的起弧性能是3种测试电极中最好的,抗烧蚀性能得到明显改善,说明电极的性能主要受ThO2含量和粒度的支配。

铜包Q195钢复合线材的组织与性能

采用复合熔铸-旋煅法制备了铜包Q195钢复合线材,通过拉伸试验、组织观察、电阻率测试等对其力学性能、组织形貌及电学性能进行了研究。结果表明:熔铸后铜和钢的结合面呈锯齿状,界面较清晰,组织较为粗大,无中间相形成,旋锻后组织细小;直径为2,3.4,4 mm的钢芯制备的铜包钢复合棒材旋锻后制得的复合线材的抗拉强度分别是260.63,368.83,419.12 MPa,电阻率分别为1.981×10^(-6),1.976×10^(-6),2.035×10^(-6)Ω·cm;旋锻后横截面上钢芯的面积比越大,其抗拉强度越接近纯钢芯的;铜包钢复合线材拉伸断口出现大量韧窝,断裂方式为典型的韧性断裂。

New extrusion process of Mg alloy automobile wheels

The recent research and development of forged magnesium road wheel were reviewed.Methods of flow-forming,spin forging of manufacturing a forged magnesium alloy wheel were introduced.A new extrusion method was investigated especially. Extrusion from hollow billet was proposed in order to enhance the strength of spoke portion and reduce the maximum forming load. By means of the developed technique,the one-piece Mg wheels were produced successfully by extrusion from AZ80+alloy.At the same time,the existing problems on the research and development of forged magnesium road wheel were analyzed.The impact testing,radial fatigue testing and bending fatigue testing results show that AZ80+wheel can meet application requirement in automobile industry.