A rotor blade includes a main body that extends radially outward from a first end to a second end, and includes a platform at the second end that extends circumferentially between opposing first and second sidewalls. The platform includes a first lateral wall that is situated between leading and trailing edges of the platform. The first lateral wall extends circumferentially between the first and second sidewalls and radially outward from the platform. The first lateral wall includes an extension that extends the first lateral wall circumferentially outward from the first sidewall. Respective portions of the first and second sidewalls adjacent to the first lateral wall reside in respective first and second planes, and the extension includes an outer face situated outside of the first and second planes. A majority of the first lateral wall includes a first material, and the outer face includes a second material having a different resistance to wear than the first material.