Are flame holders made of a special material other than that used in combustion chamber? Are the flame holders made of materials which have higher friction coefficients than the combustion chamber in order to create turbulence?
In The Jet Engine, there is no mention of a two-material setup for the flame-holder/combustor. It's all about the design of the diffuser and combustor shape / holes.

One of the fancy things they mention (p. 122, image below) is the lining of the walls in elevated ceramic-coated tiles for internal cooling.



Having to deal with two materials would decrease the structural integrity of the combuster. And to my knowledge, the flame-holder and combustor are one and the same, a single unit.