Effect of Pre-annealing on Sintering of Stainless Steel Fiber Felt

Stainless steel fiber felt is a class of unique porous metal materials. This study investigates the effect of pre-annealing on the sintering of stainless steel fiber felt through quantitative characterization of sintered joints based on synchrotron radiation experiments. The sintered joint size was found to follow a marked normal distribution in fiber felt samples sintered with and without pre-annealing. However, pre-annealing prior to sintering led to a significant reduction in the total number of sintered joints as well as a reduction in the percentage of large sintered joints. Consequently, fiber felt samples sintered with pre-annealing achieved less than half the tensile strength of those sintered without pre-annealing. Delamination through fracture of sintered joints was pronounced in fiber felt samples sintered with pre-annealing, while failure occurred mainly through fracture of individual fibers in those sintered without pre-annealing. It was concluded that sintering without pre-annealing is necessary for the fabrication of high-strength fiber felt products and the reasons are briefly discussed.