Be/HR-1不锈钢热静压高温形变的组织结构

Microstructure of Hot Deformation on Be/HR-l Stainless Steel by Hot Pressing

利用光学金相显微镜、扫描电镜(SEM)、X射线衍射(XRD)仪和材料试验机分析Be/HR-1和Be/Cu/HR-1不锈钢真空热静压接头扩散区高温形变的组织结构和性能,探讨形变组织结构与压力和性能的关系。研究表明:热静压的作用使试样产生扩散性蠕变和晶界滑动,影响扩散焊区的晶粒大小和金属间化合物的数量;热静压应不得在使基体晶粒最大的临界压力或临界应变量下进行,适当降低压力和缩短时间可减少沿晶生成金属间化合物的数量,提高连接接头质量;Be/Cu/HR-l不锈钢热静压反应扩散生成的新相熔点大大低于原基材,适当降低温度或压力可有效控制连接工件的变形。

Be/HR-1 and Be/Cu/HR-1 stainless steel were bonded respectively by vacuum hot pressing. The hot deformation microstructures and mechanical properties of their joints in the diffusion zone were analyzed by means of optical microscopy, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and material testing machines. The relationship between deformation microstructures as well as pressure and properties were discussed. Results show that hot pressing can lead to diffusion creep and grain boundary slip of the materials, and influence the grain size and amounts of intermetallic compounds in the diffusion bonding zones. Hot pressing should not be conducted under the critical pressure or critical strain which will cause maximum grain size in the matrix. The intermetallic compounds along grain boundary can be reduced by reducing holding pressure or time, and the bonding strength can be improved. The melting points of the phases formed through reactive diffusion of Be/Cu/HR-I are much lower than that of the matrix, and the deformation can be controlled by reducing holding pressure or temperature.