PSI - Issue 68

Cainã Bemfica et al. / Procedia Structural Integrity 68 (2025) 1188 – 1195 Ludovic Vincent et al. / Structural Integrity Procedia 00 (2025) 000–000

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Figure 2: Ductile to Brittle transition curves in a) Charpy V-notch impact tests and b) CT(0,5T) Fracture toughness tests. Experimental results in symbols. Tanh functions for trend curves in impact toughness. Master curves for Fracture toughness.

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Figure 3 – Comparison between the a) microhardness histograms, and b) PDF of misorientation crystallographic angles of the three alloys.

Table 3: Microhardness, crystallographic and carbide population parameters identified on MM, HMM and IM materials Material Mean Hv0.2 Std dev. Hv0.2 R ratio Grain size (µm) Ns (/µm²) α β (µm) γ (µm) MM 205 13 1.50 4.4 1.33 1.074 0.080 0.100 HMM 204 8 1.14 11.2 1.05 1.084 0.081 0.109 IM 191 5 1.14 4.8 1.05 1.042 0.081 0.108

Figure 4: Example of crack initiation on a carbide located at a grain boundary, HMM (KJc(1T) = 148 MPa √ , -30 °C). •