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

316

7

Five tensile specimens were obtained for each modality listed in Table 3, leading to 100 tensile testing specimens. Figures 7a, and 7b, present the tensile tests for the parent materials UHMWPE and PP, respectively; all tensile tests were carried out imposing 5 mm/min as constant velocity of deformation, using a Zwick/Roell tensile machine. Higher tensile strength for the parent UHMWPE was close to 26 MPa; whereas this mechanical property attained close to 32 MPa, for the parent PP. In Figures 8a, 8b, 8c and 8d are plotted the tensile strength of dissimilar welding for these two thermoplastics, corresponding to specimens: 1112, 1525, 2025 and 2525 respectively, all of them without pre-heating.

Figure 6. a) Dimensions (mm) of tensile test specimens, b) Welded specimens UHMWPE-PP for tensile tests, under the ASTM D638-14 standard.

Figure 7. a) Tensile test on the parent UHMWPE thermoplastic, b) Tensile test on the parent PP thermoplastic.

Results reveal that preheating at 80° C does not contribute to improve tensile strength of dissimilar specimens, UHMWPE-PP, joined by FSW. Pre-heating at 50° C in FSW of UHMW-PP joints, has improved the tensile strength; nevertheless, increasing to 80° C, no joining was performed [25]. Pre-heating induces material mixing and