As one of the difficulties in engine design is to prevent it from melting, one can expect research to be conducted on what materials to use for thrust chamber and nozzle.
Many engines seem to use steel and copper, or alloys like Narloy-Z, which seem to have good combinations of strength, cost and heat conduction. However, their melting point is rather low compared to other materials, such as tungsten that can go more than a thousand K higher. Other materials, like the aerogel used for Space Shuttle tiles, are also extremely heat resistant.
Those materials probably have other characteristics preventing them from using them there, though. Sure, aerogel can survive the heat, but if it is too fragile to survive chamber pressure without being torn apart, it won't be usable anyway. And tungsten may loose its physical properties well before reaching its melting point.
Are there new materials that are or have been recently developed that have better performances? Are there new approaches, like trying to make tungsten work? What material performances can we expect to see in the future?