钨铜复合材料用钨骨架的制备与压缩性能

Fabrication and compression property of tungsten skeleton for tungsten-copper composite

采用电子束选区熔化成形得到点阵结构钨样件,然后填入细钨粉松装烧结成多孔体,制备钨铜复合材料用的钨骨架,对点阵结构与多孔体的形貌与结构进行观察与分析,并测试点阵结构与钨骨架的压缩性能。结果表明:钨点阵结构的孔结构完整,孔筋内部无孔洞、裂纹等缺陷,并且组织细小。点阵结构的抗压强度高,但韧性较差,压缩过程几乎为瞬间脆性溃散。采用分段烧结的方法在点阵结构内部引入微米级多孔体,点阵结构与多孔体相互嵌套形成复合结构的钨骨架,骨架的压缩断裂经历单独点阵结构受力–点阵结构微弱变形–协同受力–开裂坍塌的过程,表现为一种混合断裂模式,避免了单独点阵结构的瞬间脆性坍塌。

Tungsten skeleton with lattice/porous composite structure was fabricated by selective electron beam melting(SEBM)together with loose powder sintering.Structure and compression property of the tungsten skeleton were studied.The results show that,the porous structure of the tungsten lattice structure is uniform,and there are no pores,cracks and other defects inside,and the microstructure is fine.The compression strength of the lattice structure is high,while the toughness is poor,which leads to almost instantaneous brittle collapse during compression test.A micro scale porous body is introduced into the lattice structure by the step sintering.The lattice structure and the porous body are embedded with each other to form a lattice/porous composite structure of tungsten skeleton.The lattice/porous composite structure shows a mixed fracture compression mode,and undergoes the process of lattice bearing force alone-lattice weak deformation-lattice/porous bearing force together-cracking and collapse during the compression test.It can avoid the instantaneous brittle collapse of the individual lattice structure.