I had my 2008 mitsubishi serpentine belt replaced (fraying). They next day, the belt broke and the mechanic stated it was due to the alternator being warped. Did the mechanic damage the alternator?

its possible but he would have to be real ruff with it

thats a good one ,I have never heard such nonsence,an altanator dosnt warp out and cause belt fail'yer lol, check and see how well all the paths of the belt line up ,if one is out of line or bent funny for (good) exampel say if the tension pully is bent or loose,pull and try to wobble each pully that belt loops around ,also look for shiny area around edges of pullys sometimes that will tell you the belt is ride'ing to high on the rim of pully and could eat belt up,useually tension pully is replaced with new belt (saves on problems acurring from loose belt), braces holding units to block can be bent if to sm. a belt is tried to be put on or if someone uses to much strength holding tension pully to put belt on ,,if your going to pay a mech money to fix your car make shure its the cetified mech and not a mech's helper that does the work,,if work was done at a known shop and no one else had touched the car talk to mang, or owner ,,old belt had no such problem with fraying I believe damage of some nature was done to my car durring maint in this shop and that damage should be eather payd for or fixed by said shop,,,chek your car out though and determin what was damaged things usually dont bend themselfs!,,if you do have bad pully or pullys is and was part of mech job to check these things and and let you know about existing problem if he didnt and you have a problem like your new belt getting ate up mech is still at falt,, and they should pay!

I went to get belt replaced at first. When they tried to replace it they said pulleys were bad. $500 for replacements of pulleys and a week later due not having tension tool, they put on belt. The next day, the belt shredded. Towed it to shop and that's when they gave my wife their explanation. They said it shredded and now the alternator needs to be replaced. I want to know did they put the belt on to tight causing the damage to alternator or do you think the alternator was bad... car is at 100000 miles! Thanks

Most likely the bearing in the alternator where the pulley attaches is worn which causes the pulley to wobble slightly causing the belt to fray and eventually break in short order. You may be able to see a shiny grove around the pulley into the housing if this is the case. It seems to be a problem with this particular vehicle. The alternators are not readily available at most parts retailers and can be quite expensive so shop cautiously.