摘要
本文研究将2种不同挤压方式(等径角挤压和传统正挤压)应用于二硅化钼电热元件的成型工艺,研究其对材料的微观组织及致密度的影响。结果显示,正挤压易出现粉末与孔隙分布不均匀,致使烧结后材料致密度低,孔隙率高,晶粒结合不够致密,微观组织不均匀;而等径角挤压技术可使材料受到均匀的纯剪切变形,同时,在烧结过程中晶粒和孔隙向各个方向长大和收缩的速率基本相同,最终使材料晶粒大小均匀,结合紧密,材料致密度提高,孔隙率降低,微观组织明显均匀化。
Applications of 2 different extrusion modes （equal channel angular extrusion and conventional forward extrusion） to the forming of molybdenum disilicide electric heating elements and their influence on the micro structure and density are studied. Testing results indicate that the forward extrusion process tends to produce an uneven distribution of powder and pores, resulting in a low density and high porosity of the material, incompact grain bonding and uneven micro structure after the sintering operation, while the equal channel angular extrusion process, on the other hand, can create an even shear deformation of the material, and the grains and pores grow or contract at every direction with roughly the same speed, bringing about an even grain size, tight bonding and compact materials with low porosity and uniform mi- cro structure.
出处
《机车车辆工艺》
2009年第3期4-6,共3页
Locomotive & Rolling Stock Technology
