A system (50, 80, 110, 120) comprising: a blade comprising a blade tip; and a blade track or blade shroud segment (24, 60, 90) comprising a substrate (30, 62, 92) and an abradable coating layer (40, 70, 102) on the substrate, wherein the substrate defines a leading edge (32, 64), and a trailing edge (34, 66), wherein the substrate defines a substantially curvilinear surface or another shape that does not include inclined portions (38a, 38b); and wherein the abradable coating layer comprises: a first tapered portion (42, 72,) that substantially continuously tapers in a direction perpendicular to the leading edge or the trailing edge from a center portion of the substrate toward the leading edge of the substrate; a second tapered portion (44, 74) that substantially continuously tapers in a direction perpendicular to the leading edge or the trailing edge from the center portion of the substrate toward the trailing edge of the substrate; and a blade rub portion (46, 76) that extends between the first tapered portion and the second tapered portion, wherein the blade tip is configured to contact at least a portion of the blade rub portion upon rotation of the blade, and wherein the abradable coating layer (40, 70, 102) extends from the leading edge (32, 64) to the trailing edge (34, 66). a blade comprising a blade tip; and a blade track or blade shroud segment (24, 60, 90) comprising a substrate (30, 62, 92) and an abradable coating layer (40, 70, 102) on the substrate, wherein the substrate defines a leading edge (32, 64), and a trailing edge (34, 66), wherein the substrate defines a substantially curvilinear surface or another shape that does not include inclined portions (38a, 38b); and wherein the abradable coating layer comprises: a first tapered portion (42, 72,) that substantially continuously tapers in a direction perpendicular to the leading edge or the trailing edge from a center portion of the substrate toward the leading edge of the substrate; a second tapered portion (44, 74) that substantially continuously tapers in a direction perpendicular to the leading edge or the trailing edge from the center portion of the substrate toward the trailing edge of the substrate; and a blade rub portion (46, 76) that extends between the first tapered portion and the second tapered portion, wherein the blade tip is configured to contact at least a portion of the blade rub portion upon rotation of the blade, and wherein the abradable coating layer (40, 70, 102) extends from the leading edge (32, 64) to the trailing edge (34, 66). a first tapered portion (42, 72,) that substantially continuously tapers in a direction perpendicular to the leading edge or the trailing edge from a center portion of the substrate toward the leading edge of the substrate; a second tapered portion (44, 74) that substantially continuously tapers in a direction perpendicular to the leading edge or the trailing edge from the center portion of the substrate toward the trailing edge of the substrate; and a blade rub portion (46, 76) that extends between the first tapered portion and the second tapered portion, wherein the blade tip is configured to contact at least a portion of the blade rub portion upon rotation of the blade, and wherein the abradable coating layer (40, 70, 102) extends from the leading edge (32, 64) to the trailing edge (34, 66).