Mechanical properties of novel calcium phosphate–mullite biocomposites

Herein, the results of systematic mechanical property measurements of pressureless sintered calcium phosphate (CaP)–mullite composites are discussed. Our experimental results demonstrated how the mullite addition (upto 30 wt%) influenced hardness, elastic modulus, strength and toughness properties of the composites. In assessing each of these fundamental material properties, either a range of load or a number of complimentary techniques were used to obtain reliable measure of mechanical properties. Importantly, the results of single edge V notch beam measurements revealed that a reliable toughness value of ∼1.5 MPa m0.5 could be obtained in composites containing 20 or 30 wt% mullite. Our results clearly illustrated that a combination of elastic modulus (∼80 GPa), compressive strength of more than 350 MPa, three-point flexural strength of 70–80 MPa, hardness of 4–5 GPa were achievable with the investigated composites. Such a combination of material properties, in addition to modest toughness property appeared to indicate that CaP–mullite composites could be used as a biomaterial for hard tissue replacement.