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

Abstract

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.

Comparison of Energy Absorption Performance and Mechanical Response of Metal Fiber Porous Materials under Two Strain Rates

“…Moreover, the failure of MFPMs with pre-annealing was determined mainly by delamination between interlayers, while that without pre-annealing was governed mostly by the fracture of an individual fiber. [13] Additionally, the tensile strength of MFPMs was improved by 50% using an innovative fast sintering process compared with the conventional sintering process. [14] Stainless steel DOI: 10.1002/adem.202201465…”

“…Moreover, the failure of MFPMs with pre‐annealing was determined mainly by delamination between interlayers, while that without pre‐annealing was governed mostly by the fracture of an individual fiber. [ 13 ] Additionally, the tensile strength of MFPMs was improved by 50% using an innovative fast sintering process compared with the conventional sintering process. [ 14 ] Stainless steel fiber felts with high tensile strength (28.4 MPa at a porosity of 83%) can be obtained using the microwave sintering method sintered at the temperature of 1000 °C and a short isothermal time of 30 min because of the microwave field effect.…”

“…[ 10,11 ] The compressive strength of MFPMs increases gradually as the porosity decreases owing to improving the numbers of metal fibers and sintered joints, and it is almost not influenced by the service temperature below 873 K, while the softening occurs at 1073 K. [ 10 ] Furthermore, the yield strength and Young's modulus of MFPMs made by coarse fiber are higher than that of fine fiber at low porosity. [ 12 ] In addition, the tensile strength of MFPMs was affected significantly by pre‐annealing prior to sintering, [ 13 ] fast sintering process, [ 14 ] microwave sintering. [ 15 ] A reduction of more than 50% in tensile strength and a decrease of almost 40% in the number of sintered joints were affirmed compared to without pre‐annealing.…”

Effect of Preannealing on Microstructural Evolution and Tensile Properties of a Novel Nickel‐Based Superalloy

“…Moreover, the effect of PA on both microstructural evolution and tensile properties in disc superalloys has been barely reported till now. The PA in other alloys was studied, such as dual‐phase steels, stainless steel fiber felt, and corrosion‐resistant superalloy . However, the effect of PA on microstructural evolution and tensile properties of disc superalloys is not clear, especially for GH4065 alloy, a novel nickel‐based superalloy used in turbine discs at the service temperature of 750 °C.…”