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...
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...
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?
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...
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...
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...
I need to get values of the specific heat capacity from a couple of gearbox oil samples at a range of temperatures (100-160°C). Initial measurements have been made using a modulated DSC, but the scatter in the results is excessive - this method is known to suffer from errors of at least 10%. Can...
My company has experienced some unexpected in service failures of hydraulic parts that previously worked fine; the failures involved cracking adjacent to core plugs. The cracks were in the short transverse plane and had the appearance of over load - ie signs of local yielding at the initiation...
I am trying to find a commercially available hydrophilic coating, such that when a drop of water is placed on the DRY surface treated with this coating that it immediately spreads out to form a very thin layer. Other less important requirements is some resistance against mild abrasion and...
Does MP35N exhibit a reasonably good relationship between hardness and tensile strength? If so can anyone point me in the direction of a good graph?
Thank you for your help
I am going to run some ambient temperature strain controlled fatigue testing (for the first time) on stainless steel (13-8PH). I am working in accordance to ASTM E606-04, but while the standard recommends testing to a constant strain rate, it does not advise a value. Could anyone provide...
Can anyone advise on a suitable experimental method for measuring the heat transfer of a particular heat pipe at different temperatures.
The best I can come up with at the moment is to locate heaters at one end, having the other end in a liquid reservoir and insulate the whole system. Then...
Is anyone able to advise on the procedure for heat treating aluminium 6101 to T64 condition (the highest conductivity form) - which is overaged compared to T6. Unfortunately internet searches have failed.
I assume the solution treatment step is 525°C for 1 hours followed by water quench. I...
We have a component that is a fabrication of both alloy 625 and alloy 718, due to the need for different requirement in certain areas. Some parts need higher strength where as others parts will be subjected to high temperatures (+900°C). Currently this is heat treated after manufacture using the...
I have been having some issues with galvanic corrosion in a coolant system of a race car (operating at approx. 120°C and 4bar), this causes problems of increasing coolant pressure due to the production of hydrogen gas in the system (accumulated gas made a pop sound when touched with a lighted...
A have two examples of the same component, that should have been manufactured from aluminium 6063 T6. One appears to be correct, but I suspect the other has been made from 6082 T6. The hardness of the later is approximately 105Hv compared to 75Hv of the former.
I am organising chemcial analysis...
I work for a company, often producing parts out of maraging steel and 13-8PH stainless steel. Unfortunately our heat treatment sub contractor are having a few power problems at the moment and there has been a couple of incidences of power loss during ageing of the above material part way through...
My company is turning a 500mm long length of 13/8PH steel bar, in condition A down from 38mm down to 12mm and the machinists have noticed that the length of the bar has reduced by 0.7mm. Note that the reason for using such large diamter bar is that the part in question has two bulbous end...
I have a part fabricated from aluminium 6082 T6, which suffers occasional cracks. We are putting a few changes in place to prevent further cracking including changing the filler rod for future parts. Also, we can afford to reduce the mechanical properties away from the weldments slightly (I...
