A bumper assembly may include a pair of crush cans and a bumper beam. The pair of crush cans are for securing to a vehicle body. The bumper beam is secured to the crush cans and includes a first end and a second end each extending outboard of one of the crush cans, and a middle portion extending between the first and second ends. The bumper beam is thermally treated to provide the first and second ends with less tensile strength than the middle portion. The middle portion may have a tensile strength between 1000 MPa and 1900 MPa. Each of the first and second ends may have a tensile strength between 600 MPa and 900 MPa.