PSI - Issue 47

Mario A. Sánchez Miranda et al. / Procedia Structural Integrity 47 (2023) 310–324 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Hardness increases or decreases with crystallinity, the stir zone during FSW of these two thermoplastics undergo higher temperatures and lower recrystallisation and, therefore, lower hardness. With aim of characterize microhardness variation (HV), along the stir zone and arounds, hardness measures were taken under the following conditions: pyramidal indenter, with applied force of 100 grams for a period of 15 seconds. Results show higher hardness values for the 1112 tests: between 3.1 and 4.1 (VH) inside the stir zone; whereas this value was comprised between 2.3 and 3.2 (VH), for the three remaining tests modalities, Figure 13.

Figure 12. Transition from brittle to ductile fracture and laminar to turbulent flow, with the tool pin temperature for the test modalities: 1112, 1525, 2025 and 2525.

Figure 13. Micro hardness evolution (HV), across the tensile specimens.