Effect of focused solar power on the structure and phase composition of a copper-based material

The change in the content, structure, and microhardness at a depth of the scale layer, which forms on the copper-based material under focused solar radiation, is studied. The formation of a structure with an external layer of CuO, Fe₂O₃, NiO oxides and mixed Cu₃WO₆ oxide (spinel type) with high microhardness H_μ = 29.4 GPa is shown. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 3–4 (454), pp. 20–25, 2007.     

铜含量对铝铜烧结材料性能影响

用粉末冶金法制备了Al-Cu合金块体烧结材料,研究了不同铜含量对烧结温度、微观形貌和抗压强度性能的影响。研究表明,对于不同铜含量的样品,存在不同的局部熔化区间。在局部熔化区间内对应一优化烧结温度。在此温度下烧结时样品仅发生局部熔化,烧结后制品外观和尺寸不会发生大的改变。烧结制品抗压强度随着铜含量的增加先上升后下降。温度为555℃时,7.5%铜含量的抗压强度达到最大值。铜元素的加入改变了烧结体内部组织和孔隙数量大小。     

温度分布对铜基摩擦材料点蚀损伤的影响

通过离合器惯性实验台耐热实验,结合对非均质粉末冶金摩擦层结构模型和温度场的分析结果,研究了特定工况下的铜基粉末冶金摩擦副点蚀损伤现象,分析了温度分布对摩擦材料点蚀损伤的影响。结果表明:湿式铜基摩擦材料在长时间过载或热负荷集中时,由于摩擦表面产生局部高温,摩擦层内部产生较大的温度梯度和热应力,在铜基体与石墨接触区域会产生裂纹并出现铜基体的脱落与转移,发生点蚀;摩擦层上的点蚀程度由外侧向内侧逐渐加重后再减轻,中部点蚀现象最严重;在同一道摩擦层上,距离径向油槽较远区域的点蚀现象严重。     

石墨含量对铜基摩擦材料摩擦磨损性能的影响

采用粉末冶金压烧技术制备了含不同质量分数石墨的铜基摩擦材料,研究了石墨含量对摩擦材料微观组织、磨损性能和磨损机理的影响。结果表明:铜基体的连续性随石墨含量增加而降低,动摩擦系数随石墨含量的增加先增加后降低,磨损量随着石墨含量的增加而减小;材料的磨损机理为犁沟式磨料磨损;石墨质量分数为16%时,试样动摩擦系数和静摩擦系数最高并且稳定,具有最好的摩擦磨损性能。     

钛含量对铜基粉末冶金摩擦材料摩擦磨损性能的影响

采用粉末冶金方法制备铜基摩擦材料,研究钛的添加量对材料的摩擦磨损性能的影响。结果表明:随着钛质量分数由3%增加到12%,铜基摩擦材料的相对密度提高,硬度增加。钛的添加导致晶格畸变,材料硬度提高。随着摩擦速度增加,材料的摩擦因数减小。钛添加到铜基摩擦材料中,降低了铜基摩擦材料的摩擦因数和磨损量,原因在于钛提高了材料的硬度,增加了表面微凸体强度,减少了犁削程度,从而降低了摩擦面的损伤程度,提高了材料的耐磨性。     

石墨对铜基粉末冶金闸片材料性能的影响

采用粒度>550μm的天然鳞片石墨和人造石墨配合制备了铜基粉末冶金高速列车制动闸片材料,系统研究了鳞片石墨粒度对材料力学性能、摩擦磨损性能和摩擦膜形成的影响。结果表明:采用粒度>550μm的天然鳞片石墨作润滑组元,所制备摩擦材料的抗压强度显著高于采用小粒度石墨所制材料,达到145.30MPa;随鳞片石墨粒度的增大,材料的摩擦系数降低,磨损率降低幅度可达50%以上,摩擦表面趋于形成完整的摩擦膜;采用鳞片石墨和人造石墨配合使用,能够显著提高材料强度。     

Production and properties of copper-based powder antifriction material

The paper examines how temperature and strain rate influence the deformation of a porous powder billet made of an antifriction material. Copper and nickel-based alloy powders produced from industrial waste are used as the initial material. The ultimate strain in compression is established and used to calculate the mold sizes in tool development. Ambiguous temperature dependence of the mechanical and antifriction properties is obtained. Temperature and strain rate that ensure satisfactory mechanical and antifriction properties are found. Processes for producing parts from the antifriction material are proposed.     

Effect of phase composition and microstructure of sintered TiN-Cr electrode material on the main characteristics of the process of electric-spark alloying of steels

Conclusions Solid solutions and the eutectic in the alloying electrode decrease its erosion during ESA, while the intermetallic compound and other brittle phases increase it. The erosion resistance of the anode grows with decrease in its porosity, and shows a correlation with the variation of its strength. A sufficiently strong bond between the phases in the heterophase material increases the latter's erosion resistance and leads to the formation of erosion products of mainly fine fractions. The presence in the anode of phases which can form iron-base solid solutions or intermetallic compounds with the basis material has a beneficial effect on the cathode weight gain. Phases which do not have this ability are retained on the cathode only when they have a strong bond with a phase (e.g., the metallic binder) which itself can form both solid solutions and intermetallic compounds with the basis.Translated from Poroshkovaya Metallurgiya, No. 4(268), pp. 32–36, April, 1985.     

铝含量对铅力学性能的影响

利用金属强化原理,设计了一组不同铝含量的铅,研究了铝(Al)元素对铅铝合金力学性能的影响.用真空感应炉冶炼出不同Al含量的Pb-Al合金,并通过快速冷却模具的手段保证成分的均匀性.基于拉伸试验、夏比冲击试验与金相分析技术等,对合金的成分、显微组织和力学性能的关系进行了测试与分析.结果表明,固溶态的Al能够有效提高Pb-Al合金的抗拉强度和冲击功,但富Al相的不均匀析出会使Pb-Al合金发生二次再结晶现象,从而导致强度、韧性的下降.