An auxiliary power unit may comprise a twin centrifugal compressor including a first blade. A turbine may be disposed aft of the twin centrifugal compressor. The turbine may include a second blade. The first blade comprises a first material and the second blade comprises a second material. The first material may the same as the second material. The twin centrifugal compressor may include forward centrifugal compressor and an aft centrifugal compressor disposed aft of the forward centrifugal compressor.