压制压力对粉末冶金钢组织和性能的影响

压制压力是制造粉末冶金材料的关键工艺因素之一,本文根据45#钢的铁碳配比,选取了5个压制压力（130,260,360,470,600MPa）,在其他工艺条件如烧结温度、烧结压力、烧结气氛、保温时间、冷却方式相同的情况下,来考察这5个工艺水平对于粉末冶金钢组织和性能的影响。试验结果表明,随着压制压力的增大,烧结体的晶粒尺寸变小并趋于均匀,材料的冲击断裂方式也由韧性断裂转变为混合断裂方式,同时烧结体的密度、硬度也随着压力的增大而出现先增大后趋于平缓的趋势。     

Testing and Quality Standards for Powder Metallurgy Products

This article enumerates the quality control methods of powder metallurgy process and testing of finished components. The standards followed in various countries and widely used in industries are compiled in this article. The information furnished here will be helpful for research workers, particularly in academic institutions that have no access to international standards.     

Effect of geometric work-hardening and matrix work-hardening on new constitutive relationship for aluminium–alumina P/M composite during cold upsetting

The densification and strain hardening behaviour during cold deformation of sintered aluminum–3.5% alumina powder metallurgy preforms were investigated by constitutive model and experimental data obtained with no and with subsequent annealing. The mechanisms most likely involved in the constitutive model, namely, densification and strain hardening were studied. The effect of geometric and matrix work hardening on the various constants involved in the constitutive model, namely, instantaneous density coefficient, instantaneous strain hardening index, instantaneous strain rate sensitivity and instantaneous strength coefficient were discussed in detail.