In situ TOF neutron diffraction during phase transformation in an engineering steel

Unravelling thermal history during additive manufacturing of martensitic stainless steel

“…Above 642 °C, the lattice parameter of the BCT increased gradually (almost linear) with a higher CTE of 19.110 10 −6 /°C. This was due to the combined effect of the transformation strain of FCC austenite (smaller volume than martensite) within the martensite matrix and thermal misfit strain [ 19 , 20 , 32 ]. During the repetitive heating and cooling up to the 5th cycle, the CTE of martensite increased slightly from 12.297 10 −6 /°C (1st) to 13.275 10 −6 /°C (5th) upon heating, and decreased from 14.486 10 −6 /°C (3rd) to 12.276 10 −6 /°C (5th) upon cooling ( Table 1 ).…”

“…4 ). It is well established that interplanar spacings are influenced by thermal expansion, the concentration of interstitial atoms, and internal stresses [ 19 , 20 , 32 , 33 ]. Regardless of the existence of retained austenite, the lattice parameter of martensite decreased continuously with an increasing number of thermal cycles ( Fig.…”

Experimental Simulation of Thermally Induced Stresses during Cooling of Continuously Cast Steel Slabs

“…Neutron diffraction is used to investigate transient thermal and transformation strains. [9][10][11] The high penetration depth of the neutron beam is essential for investigating large gauge volumes (5 Â 5 Â 5 mm 3 ) including a representative number of grains in such coarse-grained cast metals. An additional Satoh test procedure [12] is performed for the Ni containing steel to simulate the surface-near stress condition in a steel slab during transformation, where crack initiation takes place.…”

“…and α (b.c.c.) that generates significant microstresses in the microstructure at the transformation front between A c3 and A c1 temperature . Therefore, the temperature gradient and localized transformation stresses strongly influence the internal stress distribution.…”

“…A Δ T ≈ 1000 K between the surface and the slab's center creates a gradient of about 70 K cm −1 causing elasto‐plastic deformation, that is realized by the first experiment using an induction furnace setup, heating the material up to the austenite field before applying a thermal gradient by cooling. Neutron diffraction is used to investigate transient thermal and transformation strains . The high penetration depth of the neutron beam is essential for investigating large gauge volumes (5 × 5 × 5 mm 3 ) including a representative number of grains in such coarse‐grained cast metals.…”