大尺寸钨镧块烧结分层机理探究

Delamination Mechanism of Large-sized Tungsten Lanthanum Sintering

通过对大尺寸钨镧块进行4种不同工艺的烧结试验,对各个烧结坯料进行轧制处理,利用超声探伤仪、金相显微镜、SEM、EDS、ICP-AES等设备对烧结和轧制后钨镧块的密度、探伤、晶粒、弥散相、镧含量、杂质含量进行详细研究,探究大尺寸钨镧烧结层机理,并得出的结论为:升温速率快时钨镧块会出现烧结分层、整体密度低、轧制易开裂的现象;分层主要有3层:芯部层、中间层和外部层。平均晶粒尺寸、弥散相颗粒大小为中间层>芯部层>外部层。密度为外部层>中间层>芯部层。La含量为中间层>外部层>芯部层。出现该种现象的主要原因为升温速率快、内外温差大,通过减慢升温速率可以解决该问题。

Four different sintering experiments were carried out on large-sized tungsten-lanthanum blocks,and each sintered blank was rolled.The density,flaw detection,grain size,dispersed phase,lanthanum content and impurity content after sintering and rolling were studied in detail by using ultrasonic flaw detector,metallographic microscope,SEM,EDS and ICP-AES,and the mechanism of large-sized tungsten-lanthanum sintered layer was explored.The conclusion was that sintering delamination and low overall density and easy cracking of rolling would occur when the heating rate was fast.There are three main layers:core layer,middle layer and outer layer.The average grain size and dispersed phase particle size are middle layer>core layer>outer layer.The density is outer layer>middle layer>core layer.La content is middle layer>outer layer>core layer.The main reasons for this phenomenon are high heating rate and large temperature difference between inside and outside,which can be solved by slowing down the heating rate.