Methods and apparatus are provide for: a substrate having first and second opposing surfaces, and an elastic modulus; and layer(s) having a thickness between first and second opposing surfaces thereof, the first surface of the layer contacting the second surface of the substrate, forming an interface. The layer may exhibit one or more of: a first elastic modulus proximate to the first surface thereof and a second elastic modulus proximate to the second surface thereof, the second elastic modulus being substantially higher than the elastic modulus value, the first elastic modulus being lower than the elastic modulus of the substrate, the second elastic modulus being higher than the elastic modulus of the substrate, and the layer exhibiting an increasing elastic modulus gradient through the thickness thereof from the first elastic modulus to the second elastic modulus.