Metallurgical analysis of cracks on an aluminum alloy ring used in a satellite separation system
✍ Scribed by Abhay K Jha; S.V.S.N Murty; E Jacob
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 882 KB
- Volume
- 9
- Category
- Article
- ISSN
- 1350-6307
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✦ Synopsis
High strength Al-Cu alloys of the 2XXX series suit the critical requirements of structural applications in satellite launch vehicles. Copper is the principal alloying element in this alloy, often with magnesium as a secondary, addition. These alloys do not have as good corrosion resistance as most other aluminum alloys, however, they find widespread use for parts and structures requiring high specific strength. Al alloy ring of AA 2014 grade is being used for a satellite separation system in the Indian space programme. This ring consists of two lugs at diametrically opposite locations and rotates through the required angle under thrust generated by pyro thrusters. Recently, after one of the functional qualification tests of the system, both the lugs of the ring were found to be cracked. Detailed analysis revealed that a notch created by the stopper against pyro actuation played a role in crack initiation. Insufficient working during the mandrel forging operation and the presence of iron-rich particles facilitated crack propagation as revealed by fragmentation of particles and dendrite lobes on the fracture surface.