Multiple Influences of Molybdenum on the Precipitation Process in a Martensitic PH Stainless Steel
Artikel i vetenskaplig tidskrift, 2019

Molybdenum has been found to influence the complex precipitation process in a martensitic precipitation hardening stainless steel during aging at 475 degrees C in several different ways. Three steels with different Mo content (0, 1.2 and 2.3 at.%) were investigated. Studies of the microstructure were performed with atom probe tomography and energy filtered transmission electron microscopy. It is shown that, at the initial stage of aging, a faster nucleation of Cu-rich clusters takes place with increasing Mo content. The Cu-clusters act as precipitation sites for other solute elements and promote the nucleation of Ni-rich phases. During further aging, a higher Mo content in the material instead slows down the growth and coarsening of the Ni-rich phases, because Mo segregates to the interface between precipitate and matrix. Additionally, Mo promotes decomposition of the matrix into alpha and alpha' regions. After longer aging times (>40 h) quasicrystalline Mo-rich R' phase forms (to a greater extent in the material having the highest Mo content). The observations serve to understand the hardness evolution during aging.

atom probe tomography

aging

stainless steels

energy filtered transmission electron microscopy

precipitation

Författare

Mattias Thuvander

Chalmers, Fysik, Materialens mikrostruktur

Marcus Andersson

SKF Sverige AB

Krystyna Marta Stiller

Chalmers, Fysik, Materialens mikrostruktur

Metals

2075-4701 (eISSN)

Vol. 9 10 1118

Ämneskategorier

Materialkemi

Annan materialteknik

Metallurgi och metalliska material

DOI

10.3390/met9101118

Mer information

Senast uppdaterat

2020-01-13