Abstract: Aluminium-silicon powder mixtures comprising a hypereutectic Al—Si powder, a near eutectic Al—Si powder, and a third powder which is aluminium or a hypoeutectic aluminium alloy containing alloying constituents other than silicon and less than 9 wt % silicon, with a sintering aid comprising a fourth, zinc-containing powder, are pressed and sintered to provide powder metallurgy products suitable for automotive component use in particular. The third powder in the composition permits such Al—Si powder mixtures to be compressed to a density approaching that obtained by use of an annealed powder mixture, but without the annealing step.

Abstract: Aluminium-silicon powder mixtures comprising a hypereutectic Al—Si powder, a near eutectic Al—Si powder, and a third powder which is aluminium or a hypoeutectic aluminium alloy containing alloying constituents other than silicon and less than 9 wt % silicon, with a sintering aid comprising a fourth, zinc-containing powder, are pressed and sintered to provide powder metallurgy products suitable for automotive component use in particular. The third powder in the composition permits such Al-Si powder mixtures to be compressed to a density approaching that obtained by use of an annealed powder mixture, but without the annealing step.

Abstract: A method of making a sintered article is disclosed, the method comprising the steps of mixing a prealloyed ferrous powder having a composition in the following ranges in weight %: carbon 0.7-2.7/chromium 3-6/cobalt 5-10/vanadium 0.5-3/molybdenum 6-11/silicon 0.3-2/ others total 2 max/balance iron and optionally up to 3 wt % tungsten, with an addition of carbon powder of at least 0.1 wt %, compacting said powder mixture by uniaxial pressing to form a green compact of near net shape, sintering said green compact in a continuous gas atmosphere sintering furnace at a temperature in the range from 1130.degree. C. to 1250.degree. C. such that the final density of said sintered material is greater than 95% of the theoretical density as a result of the sintering operation alone.

Abstract: A method of making an article by joining together at least two porous components is described, the method comprising the steps of making at least two generally tubular PM components to be joined in the axial direction, each component having an axial length less than that of the tubular article; the at least two components both having interconnected porosity and each having at least one mutual mating face; assembling the at least two components together so that the at least one mutual mating faces are in proximity to each other; placing an infiltrant material in the bore of the assembled components; heating the assembled components to melt the infiltrant material and cause it to infiltrate the interconnected porosity at least in the region of the mutual mating faces so as to cause the components to become bonded together by the infiltrant material. Examples of the manufacture of valve guides are given.