A criterion to find crack-resistant aluminium alloys to avoid solidification cracking

Aluminium alloys are susceptible to solidification cracking. A criterion was derived to determine whether an aluminium alloy is susceptible to cracking utilising a recently proposed cracking index, maximum │dT/d(f_S)^1/2 │ near (f_S)^1/2 = 1 where T is the temperature and fs is the fraction of solid, and aluminium-binary phase diagrams under limited solid diffusion conditions. If the maximum │dT/d(f_S)^1/2 │ of an aluminium alloy is equal or less than 1423°C, it has good crack resistance to solidification cracking. The criterion was used to determine the critical amount of the filler metal 4043 Al to reduce the crack susceptibility of 6061 Al with the help of commercial thermodynamic software and database.