**Fractographic Examination**

**Figure A1.** The quasi-cleavages, which are characteristics of fatigue failure (SEM).

**Figure A2.** Topographical SEM image of the CS1 at the fracture surface showing the damage origin and the details of interest at the fracture surface.

**Figure A3.** Topographical SEM image of the CS1 showing striations.

**Figure A4.** Topographical SEM image of the CS1 showing a microcrack at detail 2 (**left**). Detail 3 (**right**) showing striations with a severely rubbed surface.

**Figure A5.** Topographical SEM image of the CS4 showing the details of interest at the fracture surface.

**Figure A6.** Topographical SEM image of the CS4 showing striations.

**Figure A7.** Topographical SEM image of the CS4 showing detail 1 (**left**). Detail 2 (**right**) showing striations.

**Figure A8.** Topographical SEM image of the locking screw (LC) showing the damage origin and the details of interest.

**Figure A9.** Topographical SEM image of the locking screw (LC) showing highly mechanically rubbed surfaces (**left**) with some striations on detail 3 (**right**).

**Figure A10.** Topographical SEM image of the locking screw (LE) at the fracture surface showing the damage origin and the details of interest.

**Figure A11.** Topographical SEM image of the locking screw (LE) showing detail 1 (**left**). Detail 2 (**right**) showing some striations.
