High-temperature strengthening mechanisms of Laves and B2 precipitates in a novel ferritic alloy

摘要: Abstract Precipitates of the Laves and B2 phases were engineered in a newly-designed advanced ferritic alloy. Under creep test at 650 °C with 120 MPa, material showed steady-state minimum rate 1 × 10−4 h−1, about one order magnitude lower than T91. Microstructural characterization alloy revealed primarily ductile partially brittle fractures after test. Coarse phase (~ 1 µm) was observed associating fracture, resulting reduced ductility. However, fine precipitates 100 nm) helped dimple-ductile fracture strengthened through impeding motion dislocations boundaries. Unlike remained coherent exerting classic Orowan bypassing mechanism location, some location became incoherent can develop an attractive interaction dislocations. This coherency change precipitates, together nucleation ultrafine 40 nm) during test, would compensate for coarsening-induced loss strengthening precipitates.