2 is also selected in compliance with composition no 2 this adds the effect of zirconium that in addition to its propensity for stabilizing the alpha phase of titanium also appears to present an affinity with oxygen that is advantageous such that the zirconium acts together with the hafnium to capture the oxygen and thus avoid the precipitation of oxidizing phases of aluminum and titanium the combined presence of these two elements also appears to present a synergy effect further reducing the segregation of the species constituting the alloy during cooling of the alloy finally the following alloy no 3 is selected in accordance with composition no 3 although it is in the same column of mendeleev 39 s table as zirconium or hafnium silicon also appears to have a beneficial effect in opposing the precipitation of oxidizing phases of aluminum and titanium in the alloys taken as examples of the compositions the proportions are given to within u00b1 10 in relative value for example in alloy no 1 the proportion of aluminum lies in the range 6 3 to 7 7 and the proportion of hafnium lies in the range 0 81 to 0 99 using these alloys it is proposed to fabricate half finished products by successive forging operations in the u03b2 u03b1 u03b2 u03b2 u03b1 u03b2 zones with final deformation in the u03b1 u03b2 zone the product as forged in this way is then subjected to the following heat treatment temperature raised to 790 u00b0 c pause at said temperature for 3 h cooling in air pause at 560 u00b0 c for 8 h and cooling in air the invention is naturally not limited to the above description although the compositions and alloys described in detail include vanadium molybdenum chromium and iron the invention also covers alloys.