If aluminium suffers from stress fractures quite easily, then how come it is considered and used in high performance

Question: If aluminium suffers from stress fractures quite easily, then how come it is considered and used in high performance engines that are put under alot of heat, wear and if a turbocharged engine, very high boosts?
- Keywords:
  aluminium,
  engines,
  fractures,
  heat,
  performance,
  turbocharged
Asked by King Julian to Matt on 5 Mar 2018.
- Matt Bawn answered on 5 Mar 2018:
  
  This isn’t really my area but I’ll try and answer as best I can. From what I have read aluminium has two particular properties that make it useful in high performance engines:
  
  1. It is much lighter than iron or steel
  2. It has better thermal properties for some applications
  
  This article is quite good:
  
  http://articles.latimes.com/1992-03-18/news/vw-3712_1_aluminum-engines
  
  Yes as you mention it can degrade under high temperatures etc. but manufacturers try and improve engineering processes and design to mitigate this. i.e. new alloys or coatings. (ferrari uses 7 per cent silicon and a trace of iron to improve mechanical integrity.) These things are obviously expensive which is why they are predominantly used in high-performance engines and not so widespread.

Question: If aluminium suffers from stress fractures quite easily, then how come it is considered and used in high performance engines that are put under alot of heat, wear and if a turbocharged engine, very high boosts?