Hugh,

It was agreed here, in other threads, that the process termed 'annealing', needs temperatures of 600 degrees Celsius.
Therefore it cannot take place in any type of engine (except in jets...).

But in those meehanite piston engines, low heat cycling does achieve the longest possible life expectancy.
I do not know what to term the process, but a superior seal and superb wear resistance are the result.

Duke Fox reputedly ran a .35 through many, many gallons of fuel, without any noticeable wear on the engine.

I don't think there is any heat treatment process that takes place in high silicon (hyper-eutectic) aluminium pistons.

Besides, lets start a new thread, based on Mr. Higley's and the late Mr. Aldrich's notes on break-in of lapped engines.
Since I am less experienced in these engine types, maybe another distinguished RCU member will volunteer to start it.