THE TRANSFORMATION CHARACTERISTICS OF A BETA-PHASE TITANIUM ALLOY. Technical Report No. 3 on PHYSICAL METALLURGY OF TITANIUM ALLOYS
The transformation behavior of a titanium alloy containing 11% chromium, 13% yanadium, and 4% aluminum was investigated by hardness measurements, x ray diffraction and metallography. The solution treated alloy consisted entirely of beta phase. Aging at temperatures between 700 and 1150 deg F increased the hardness; the rates of hardening suggested that beta decomposed by different modes upon aging above 1050 and below 900 deg F and by a combination of these modes between these temperatures. X-ray-diffraction analysis indicated that in the upper-temperature range the reactions beta -- beta , + alpha -- beta / sub u/ + alpha + TiCr/sub 2/ occurred, whil e in the low-temperature range, the transition phase omega appeared and the reactions were beta -- beta , + omega -- beta /sub u/ + alpha . Two modes of decomposition were also suggested by the microstructures. A TTT diagram is proposed on the basis of these results. The hardening is attributed to the precipitation of omega and alpha and to solid solution hardening of the remaining beta. An increase in solution time did not change the hardness of the solution treated specimens but decreased the rate of subsequent hardening. Cold working of solution treated specimens accelerated hardening and raised the hardness level attained. (auth)
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge. Dept. of Metallurgy
- DOE Contract Number:
- NONR-1841(02)
- NSA Number:
- NSA-14-003796
- OSTI ID:
- 4198935
- Report Number(s):
- NP-8094
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-60
- Country of Publication:
- United States
- Language:
- English
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