f 1200 u00b0 f near isothermal run described in example 4 were machined to provide high cycle fatigue test specimens the samples were tested at 70 u00b0 f at a frequency of 30 hz using an a ratio of 0 99 baseline cast plus hip 39 ed samples no hydrogen treatment were machined and tested from the same heat of alloy for comparison purposes the results of this work are illustrated below and compared with the reported properties of wrought material in fig1 ______________________________________70 u00b0 f high cycle fatigue properties ofcast and hip 39 ed ti 6al 4v alloy maximum cyclematerial stress tocondition 1 ksi failure comments______________________________________control 60 10 sup 7 did not failmaterial 2 60 10 sup 7 did not fail 65 10 sup 7 did not fail 65 9 3 u00d7 10 sup 6 75 4 3 u00d7 10 sup 5 75 3 4 u00d7 10 sup 5 80 1 7 u00d7 10 sup 5treated according 90 10 sup 7 did not failto the invention 3 100 10 sup 7 did not fail 100 10 sup 7 did not failtreated according 100 10 sup 7 did not failto the invention 4 100 10 sup 7 did not fail 110 10 sup 7 did not fail 110 5 2 u00d7 10 sup 6 110 4 5 u00d7 10 sup 6 110 3 7 u00d7 10 sup 6 110 2 2 u00d7 10 sup 6______________________________________ 1 after casting and hip at 1650 u00b0 f and 15 ksi for two hours 2 tests performed for production heat characterization purposes after 1550 u00b0 f anneal for two hours 3 isothermal processing at 1450 u00b0 f with an average constitutional quenching rate of 0 32 per hour as described in example 2 4 near isothermal processing at 1550.