论文部分内容阅读
0 前言许多高级合金、陶瓷的和合成材料的部件,如今都是用粉末冶金的方法制造,面粉末的凝熔(如用热等静压或真空热压),则往往是部件制造的最后一道工序。凝熔工艺条件(压力和温度)决定了部件的微观组织和它们的特性,尤其是对结构件高温机械性能起决定性作用的空隙量和组织的粗化程度。热等静压或真空热压过程中组织的粗化是由于试件加热到绝对熔化温度的50～70％(利用蠕变机构消除空隙)时,为晶粒增长和其它粗化物扩散提供了足够的条件所致。因为最终的晶粒尺寸取决的粉末原始特性(残余杂质、粒度、位错密度,……)均未知而且在凝熔周期内(如初始密度、冷却压力、加热速率、……)作微妙的变化,又加上每批粉末的原始条件和凝熔条件不同,所以晶粒尺寸往往也有所不同。据此,兴起中的材料智能化加工过程的设想是:探索应用综合的预处理模式,传感器和控制
0 INTRODUCTION Many advanced alloy, ceramic and composite parts are now manufactured by powder metallurgy and the final melting of the flour (such as hot isostatic pressing or vacuum hot pressing) is often the last component manufacturing process Process. Condensation process conditions (pressure and temperature) determine the microstructures and their characteristics of the components, particularly the amount of voids and the extent of roughening of the tissue, which play a decisive role in the high temperature mechanical properties of the structure. The coarsening of the tissue during hot isostatic pressing or vacuum hot pressing is due to the fact that when the specimen is heated to 50 to 70% of the absolute melting temperature (elimination of voids by means of a creep mechanism) sufficient grain growth and other roughening are provided Due to the conditions. Because the final grain size depends on the original properties of the powder (residual impurities, grain size, dislocation density, ...) are unknown and subtle changes in the melting cycle (such as initial density, cooling pressure, heating rate, ...) , Plus the original conditions of each batch of powder and coagulation conditions are different, so the grain size is often different. Based on this, the idea of an intelligent materialized process in the rise is to explore the application of integrated preprocessing modes, sensors and control