Cracking was not noticed during or immediately after installation of the stud, but was discovered after a short in-service period. It is a cut thread. I am more interested in the appears of the fracture surface shown in the SEM images - it is not typical of ductile overload.
I would be interested to hear comments/ thoughts/ opinions on the attached images of a fracture surface of a 7075 T6 component. The part was machined from a piece of plate and failed in the short transverse direction. It appears to have cleaved at the grain boundaries; I am confident the...
Thank you for your replies. Further testing with more appropriate data logging has confirmed creep. I appreciate the temperature is very high, but the service life of the parts are only of the order of 10 hours.
The test specimens are typical uniform gauge length, round fatigue specimens with...
I am currently fatigue testing aluminium 6061 at 250°C. Frequency 25Hz and stress ratio 0.1. The specimens are being tested in the elastic range. The failure mechanism of the samples is not cracking and braking in two, but by yielding and necking in the gauge length area.
Initially, I assumed...
If we approach this from a different direction. The structures personnel in my company wishes to obtain some 'toughness' values for range of material. They will not be used for design purposes, but to provide some information on the relative 'robustness' or 'tolerance' of components made from...
Further to my last reply. E399, contains recommended sizes to ensure plane-strain in the specimen, E1820, does not as it no longer covers plane-strain. If my requirement is just to compare the toughness of different materials (SiC particulate reinforced aluminium, with diffrent reinformace...
The intention is to compare the toughness between three different, but similar materials. I am reading through E1820 and E399 and I have to say I am getting lost!!
I am looking to undertake some fracture toughness testing of aluminium metal matrix composites (SiC particulate reinforcement). There are a number of test standards, ie. ASTM E399, ASTM E1820, BS 7448 etc.
Have anyone undertaken these tests and are able to advise on the pro and con of each test...
I would be interested in views on the way keenserts should be installed into continuous fibre reinforced composites. Do people believe the locking keys should be used (despite the additional damage caused to the fibres)or should the key be removed and the insert just be bonded into the composite?
Metengr: Thank you for the paper it looks very useful - it will be interesting to compare the parameters I get using this approximation against my fatigue results.
Although I would still be interested in getting any advice from anyone with experience with conducting strain fatigue tests.
I am currently looking at some 7075 T6 strain controlled fatigue test data to obtain the following parameters: -
Cyclic strain hardening exponent
Fatigue strength exponent
Fatigue Ductility exponent
Cyclic strength coefficient
Fatigue strength coefficient
Fatigue Ductility coefficient
Whilst...
Ceramicguy,
Could you advise on suitable surface analysis tools, this is the first time I have dealt with ceramics. I usually work with metals and composites and is those cases, to examine the surface I would usually use SEM and FTIR respectively.
Regards
Carl W
My company is making use of aluminium nitride plates (of approx. size 6mm x 20mm by 0.6mm thick) for a thermally conductive, but electrically insulating interface for a high voltage device. In controlled conditions these parts work well, but in other environments we have observed varable...
The part is a fabricated tube with a wall thickness of less than 1mm, although some of the machined parts that have been welded on have a section thickness of around 5mm.
TVP,
No I had not read that reference thank you - it has given some food thought. There will be some machined components welded on to formed sheet, which in turn will not be subject to large deformations, so based on the document from Haynes a full solution treatment may not be the best thing...
I am looking to design a part that will be manufactured from cobalt alloy 188 (ie Haynes 188, Udimet 188..). This will be operated at temperatures between 700 and 1050°C. Would the standard final heat treatment of holding at 1175°C for 30minutes followed by fast cool be appropriate for the...
Yes - sealed pans are being used during the tests. The results look good during a single test, ie. a consistent rise in SHC with temperature and there is no anomaly at the higher temperatures. Therefore I believe it is unlikely there is breakdown of the oil. The problem is scatter from one test...
