The present disclosure relates to a method of heat treating a component (e.g. a combustor tile) which may be formed of a first material e.g. a nickel superalloy. The component may be formed using an ALM method. The method comprises enclosing at least part of the component in a foil envelope which may be formed of a second material wherein the second material (e.g. stainless steel) is more susceptible to reactive oxidation than the first material. Next the envelope is purged with an inert gas (e.g. argon) and the envelope is sealed. The component is then heated e.g. using hot isostatic pressing.