Investigation on 316L/316L-50W/W plate functionally graded materials fabricated by spark plasma sintering

Tungsten plate (Wp), tungsten powder (W) and stainless steel 316L (316L) were used to fabricate 316L/W composites, respectively. Due to the less pores for the interface of 316L/Wp, Wp was used to fabricate 316L-50W/Wp as well as 316L/316L-50W/Wp. All samples were sintered for 5 min under conditions of 1050 °C and 45.5 MPa by spark plasma sintering method. Morphology and elements distribution of the interfaces were investigated by optical microscope, SEM and EDS. The hardness distribution for 316L/316L-50W/Wp functionally graded materials was also studied. Results revealed that there were residual pores for the interface of 316L/W. Homogeneous interfaces with less pores could be obtained for 316L-50W/Wp and 316L/316L-50W/Wp with 316L-50W milled nearly 5 h. Longer milling time leads to more intermetallics, holes and micro-cracks at the interface, which is neither beneficial to obtain homogeneously distributed joints nor suitable to gain graded interfaces. The hardness analysis result gives the same conclusion as well.