The turbine exhaust case (TEC) mixer assembly for an aircraft engine includes a center body including a hub that encloses a center body cavity and has a first wall portion and a second wall portion that are axially spaced apart. The first and second wall portions having axial end segments which are removably coupled to each other radially inwardly from the outer periphery of the center body via a fixing arrangement including a fastener that is enclosed within the center body cavity. An axial spring includes a gap axially defined between portions of the axial end segments and located at the outer periphery of the center body. A mixer extends peripherally about the center body and is spaced radially outward from the hub by a plurality of struts extending between the hub and the mixer, the plurality of struts being axially offset from the gap at a strut-hub interface.