A medical device, such as a medical guidewire, having a portion including an inner zone of material and an outer peripheral zone of material surrounding the inner zone of material. The inner zone of material has a first coefficient of thermal expansion and the outer peripheral zone of material has a second coefficient of thermal expansion less than the first coefficient of thermal expansion, wherein at an operating temperature the outer peripheral zone of material opposes expansion of the inner zone of material such that the outer peripheral zone of material exerts a compressive stress on the inner zone of material.