| 摘要 |
<p>A gamma titanium aluminide alloy consisting of 46at% aluminium, 8at% niobium, up to 0.07at% carbon and the balance titanium plus incidental impurities has an alpha transus temperature T alpha = 1335 DEG C. The gamma titanium aluminide alloy was heated to a temperature T1 = 1360 DEG C and was held at T1 = 1360 DEG C for 1 hour or longer. The gamma titanium aluminide alloy was fluidised bed, or salt bath, quenched to a temperature T2, where 900 DEG C < T2 < 1200 DEG C, and was held at temperature T2 for a sufficient time to allow the massive transformation to go to completion. The gamma titanium aluminide alloy was heated to a temperature T3 = 1300 DEG C or 1320 DEG C and was held at T2 for 4 hours. The gamma titanium aluminide alloy was air cooled to ambient temperature. The gamma titanium aluminide alloy has a fine duplex microstructure comprising differently orientated alpha plates in a massively transformed gamma matrix. The heat treatment reduces quenching stresses, allows larger castings and a broader range of titanium aluminide alloys to be grain refined. <IMAGE></p> |
