C172 pilot reported an electrical malfunction which resulted in smoke in the cockpit and loss of radio communication with ATC. The pilot returned to the departure airport and landed; then taxied to the hangar.

Narrative

At approximately XA:30; I conducted a pre-flight of Aircraft X in accordance with the checklist and proper fuel and oil levels. I then started the aircraft; conducted a pre-taxi check; and received a taxi clearance to Runway XX from the ZZZ ground controller. While holding short of Runway XX; I conducted my pre-takeoff and engine runup check; which included checking for magneto function; normal engine operating conditions; and electrical. The alternator gauge displayed standard indications prior to takeoff. At approximately XB:00; I received a takeoff clearance from ZZZ. I departed runway XX in a standard takeoff configuration and departed to the SE to pick up a pipeline that started 9.0 NM bearing 185 degrees from ZZZ1. After departing ZZZ; I contacted the ZZZ Departure and advised them of my flight route through ZZZ1. At approximately XB:15; 3.0 nm E of ZZZ1; I began to experience transponder/ GPS failure and attempted to establish contact with ZZZ departure to report my situation. Soon after experiencing the Transponder/ GPS failure; I began to experience intermittent radio communication failure. I attempted to advise ZZZ of my decision to return to ZZZ prior to my complete radio failure. I was unable to squawk an emergency code due to the electrical failure. Soon after my radio failure; I began to smell smoke and decided to turn off the Avionics master and master battery/alternator switch to prevent the risk of fire. At around XB:20; I landed runway XX at ZZZ; exited the runway; and then taxied to the hangar. After shutting down; I conducted a post-flight inspection of the aircraft and found a metal clunking noise being produced by the prop when it was moved.