2007 PT Cruiser Control Arm-Bushings-Ball Joints

Yesterday mechanic replaced lower control and bushing moog and aligned. Today making a u-turn ball joint broke, had to be towed. Is the ball joint break a result of faulty repair yesterday?

not enough info.
Lower control ? ? ?
is that perhaps a lower control ARM ?
which arm was replaced and which ball joint broke ?

A lower control ARM is an assembly with the ball joint and two bushings.
Your tech would have a parts warranty issue with his supplier - IF - that same arm broke its ball joint.
BUT . .
A tie rod end is a ball-style joint but not refered to as such . .YET . . I’ve had many a customer call it it that untill we get the diagram on the screen and they point to the tie rod end as beeing the ‘‘ball joint’’ they are wanting. ( even sway bar links can have a ball-style joint )

It could easily be that , since the front end needed THIS part that other parts are not far behind in time and mileage to be breaking soon.
You could have broken something else.

Whatever component totally failed should have been caught while doing the alignment.

When an alignment is performed, the tires are pointed straight ahead while sitting on turn-tables.

Then once the alignment is set to specs, the steering wheel is turned from-lock-to-lock and then returned to straight ahead. If there’s any worn steering/suspension components, the alignment will go out of specs indicating a problem.

Tester