ISSN:
1573-8973
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Conclusions 1. Addition of rhenium in quantities from 0.5 to 36% into molybdenum does not result in monotonic reduction of the metal cold brittleness threshold in its cast condition (T b u ), as this is usually suggested in technical literature [5, 6, 9]. 2. In introducing rhenium into molybdenum an increase is observed in the temperature range of transition of cast metal from plastic to brittle state. This increases T b u and reduces T b l with the exception of alloys containing 4–6% Re whose T b u corresponds to T b u of pure molybdenum. 3. An increase of T b u in adding rhenium to molybdenum is connected with increased values of σ0·2 in the higher temperature region of the cold brittleness range, while a reduction of T b l is caused by a marked weakening of the temperature sensitivity σ0·2. 4. The retention of plasticity down to lower temperatures with a high rhenium content (36%) is associated with the additional mechanism of strain-twinning. In alloys with a lower rhenium content (0.5–20%) twinning is not observed. 5. At all temperatures below T b u the character of fracture of alloys, regardless of their rhenium content, is brittle, transcrystalline and differs little when the test temperature changes from T b u to T b l . An increase in plasticity during transition from T b l to T b u leads to the appearance in the fracture of traces of a preliminary plastic strain with the general brittle nature of fracture retained. At temperatures above T b u the specimens bend with α=120°C without fracture, consequently, the Mo−Re alloys like pure molybdenum develop no tough fracture.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00715883
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