Hardness and elastic modulus gradients in plasma-nitrided 316L polycrystalline stainless steel investigated by nanoindentation tomography

Dependence of nanoindentation hardness with crystallographic orientation of austenite grains in metastable stainless steels

“…For example, the hardness and elastic modulus anisotropy of plasma-nitrided AISI 316L stainless steel as a function of the crystallographic structure has been reported by Tromas et al [29], and Taylor et al [30] have evaluated the hardness of grains in dual phase steels. There are a few reports on the mechanical behaviour of the individual austenite grains in TRIP steels too [3,31,32], but all of them deal with the most extended group of steels with TRIP effect, those with ferritic matrix.…”

Microstructure dependent elastic modulus variation in NiTi shape memory alloy

“…The present study aims at exploring the physics behind modulus variation in NiTi shape memory alloy. Nano dynamical mechanical analysis (Nano DMA) has been proven to be a good scientific method to explore the micro level dependence on the mechanical properties [12,13]. In the present investigation, the estimation of elastic modulus has been carried out using nano DMA.…”

From Micro to Nano Scales -Recent Progress in the Characterization of Nitrided Austenitic Stainless Steels

“…Whereas the former can be applied to determine the nitriding induced surface hardening [31,[48][49][50][51] and the depth profile of hardness in the nitride cross-sections [51,52], the latter is also capable of measuring the elastic modulus [53,54]. Figure 3 shows the depth profiles of Knoop microhardness of plasma nitrided AISI 316 steel samples out of the authors' recent research.…”

“…On the sample nitrided at 400°C, nano-indentation determined a maximum hardness value over 15 GPa at the depth of ~4 µm, which gradually Wang et al found that, the case depth of DC plasma nitrided AISI 304 steel increased almost linearly from 5 to 12 µm along the increase of nitriding temperature from 350 to 500°C, whereas the maximum hardness (HV 0.1 1000-1200) was obtained at the nitriding temperature 460°C [57]. Stinville et al developed a technique of 2-D nano-indentation matrix measurements, SEM EBSD imaging and stress-less electro-polishing, to measure the 3D anisotropic changes in hardness and elastic modulus of plasma nitride 316L polycrystalline stainless steel and found that, the E modulus and hardness measured on individual grains depend strongly on their crystalline orientations [53,54]. The E modulus and hardness values of the nitride steel were 220-240 GPa and 13-16 GPa respectively depending on the crystalline orientation, comparing to the E modulus (190-215 GPa) and hardness (1.8 -2.2 GPa) of the un-nitrided steel.…”