Fixed support at just one end defined a long cantilevered structure which doesn't represent the physics of the real part. Replace fixed support with a zero displacement on three faces, the two cut faces and the flat base.
I added a Modal Analysis so you can see the the effect of the three displacement supports. I suppressed the Fixed Support. But if you suppress the three displacements and unsuppress the fixed support, you can see in the Mode Shapes the freedom that the fixed support allows is too great and does not at all represent how this slice works with the rest of the nozzle. The displacement supports allow the nozzle to expand radially outward with the thermal temperature because the nodes are allowed to slide in the plane of the cut. But the displacement supports on the cut also support the pressure load by allowing hoop stress to build up in the nozzle. With just a fixed support, those pressure loads were trying to bend a cantilevered beam instead of stretch a revolved solid.
That lets the Transient Structural solve, at least for the first 0.8 seconds, when I stopped the solution so I could archive it and send it back to you.
Attached is an ANSYS 18.2 archive.