37 has been produced by slm the metal lattice structure 33 is a multi layered mesh structure made from a titanium alloy the metal lattice structure 33 comprises interstitial spaces 39 into which a powder can be infiltrated the metal lattice structure 33 has a porosity of 75 by volume with a mesh size of 4 mm the warhead casing 37 has a dense metal top 36 to provide dimensional stability in fig5 a lattice 41 is formed from a metal powder 42 by slm 43 a metal powder 44 and a fluoropolymer powder 45 are mixed blended and milled 46 and infiltrated into the lattice 41 using hot or cold isostatic pressing 47 the resulting composite is finished by machining 48 to produce a warhead component 49 whilst the present invention has been described and illustrated with reference to particular embodiments it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein for example the metal lattice structure may have a porosity of 50 by volume with a mesh size of 3 mm or a porosity of 25 by volume with a mesh size of 2 mm where in the foregoing description integers or elements are mentioned which have known obvious or foreseeable equivalents then such equivalents are herein incorporated.