镍的合金化方法对铁基合金组织和力学性能的影响

针对Fe-1.75Ni-0.50Mo-1.5Cu-0.6C粉末冶金合金,采用羰基Ni粉混合和水雾化预合金化两种方法添加Ni元素,研究Ni元素的合金化方式对该合金组织和性能的影响。结果表明:在相同的条件下,由Ni预合金Fe粉制备的烧结合金密度和抗拉强度较低,硬度较高,组织为均匀的珠光体和铁素体混合组织;而由羰基Ni粉混合合金化方法制备的烧结合金密度和抗拉强度都有提高,硬度略有降低,金相组织为分布不均匀的珠光体和铁素体,在原始Fe粉粉末颗粒周围存在富Ni区。

用粘结剂处理的预合金Mo钢基预混粉取代扩散粘结粉

现已采用成本较低的粘结剂处理预混粉FLOMET 4 4A和 4 4B取代扩散粘结粉。为避免镍与铜的偏析和改善预混粉的流动性 ,将以 0 .85 %Mo预合金ATOMET 4 4 0 1作基体粉 ,并添加镍、铜与石墨制取的预混粉进行粘结剂处理 ,其性能类似于扩散粘结粉。FLOMET 4 4A和 4 4B已用于制造汽车、电动工具与农机零件。研究了它们的压缩性、重量稳定性、力学性能与显微组织 ,并分别与含 1.75 %Ni和 4 .0 %Ni的扩散粘结粉做对比。低成本的粘结剂处理预混粉其尺寸变化、稳定性和力学性能与扩散粘结混合粉相同。

制造零件用的铬钢粉

作为一种合金化元素,铬由于价格低廉、淬透性高及可重复利用,具有重要意义。近年来,预合金化铬粉由于价格低容易得到,用途在增多。总的生产成本低这是将零件从钢材转为粉末冶金材料的驱动力。通过采用预合金化铬材料,和常规钢零件相比,粉末冶金产业将进一步增加其市场的份额。这篇论文考察了二种预合金化铬铁粉,一是用于高强度应用的含3%Cr与0.5%Mo的Astaloy CrM,另外一种是用于中等强度应用的含1.5%Cr与0.2%Mo的Fe-1.5Cr-0.2Mo。说明了上述材料在含碳量为0.2%～0.8%范围的力学性能。

Application of pre-alloyed powders for diamond tools by ultrahigh pressure water atomization

Copper, iron and cobalt based pre-alloyed powders for diamond tools were prepared by ultrahigh pressure water atomization（UPWA） process. Pre-alloyed powders prepared by different processes including UPWA, conventional water atomization （CWA） and elemental metal mechanical mixing （EMMM） were sintered to segments and then compared in mechanical properties, holding force between matrix and diamond, fracture morphology of blank and sintering diamond section containing matrix. The results showed that the pre-alloyed powder prepared by UPWA exhibits the best mechanical properties including the relative density, the hardness and the bending strength of matrix sinteredsegment. Sintered segments fractography of UPWA pre-alloyed powder indicatesmechanical mosaic strength and chemical bonding force between the pre-alloyed powder and the diamond, leading to the great increase in the holding force between matrix and diamond. The mechanical performance andthe service life of diamond tools were greatly improved by UPWA pre-alloyed powders.