A polycrystalline diamond (PCD) composite compact element 100 comprising a substrate 130, a PCD structure 120 bonded to the substrate 130, and a bond material in the form of a bond layer 140 bonding the PCD structure 120 to the substrate 130; the PCD structure 120 being thermally stable and having a mean Young's modulus of at least about 800 GPa, the PCD structure 120 having an interstitial mean free path of at least about 0.05 microns and at most about 1.5 microns; the standard deviation of the mean free path being at least about 0.05 microns and at most about 1.5 microns. Embodiments of the PCD composite compact element may be for a tool for cutting, milling, grinding, drilling, earth boring, rock drilling or other abrasive applications, such as the cutting and machining of metal.