A prototype aluminum composite brake rotor has been developed that could weigh 60 percent less than cast iron rotors, last three times as long, and could be cheap enough for the mass market.
The rotor is the result of joint research by the metal matrix composite maker REL and a team at the Polytechnic Institute of New York University (NYU-Poly). It is made from a new fiber-reinforced metal matrix composite designed for volume manufacturing applications. The researchers say the composite rotors would cut about 30 pounds overall from the average midsize sedan. They may also help reduce weight in military armored vehicles, which would help their fuel last longer in situations where fuel delivery is difficult.
An aluminum composite brake rotor that weighs 60 percent less than cast iron and lasts three times as long is expected to cut about 30 pounds from midsize sedans.
(Source: NYU-Poly)
The expense of composite brakes has limited their use to motorcycles, race cars, and high-performance sports cars. The researchers specifically set out to create a material that is easier to manufacture, and they designed the fiber reinforcements for a longer life span. Making automotive brake components more durable has been a longstanding research goal, since they must operate in an environment with tremendous temperature and pressure changes.
REL, which makes transportation and aerospace components out of metal matrix composites, received a $150,000 Phase I Small Business Innovation Research Grant from the National Science Foundation to come up with the initial product design, the metal matrix composite material, and the manufacturing process. The NYU-Poly research team consists of Nikhil Gupta, an associate professor of mechanical and aerospace engineering, and students in his Composites Materials and Mechanics Lab. The team helped to develop the technology for automotive applications.
Most brake rotors are made of cast iron, a strong material that weighs a lot and does not respond well to the varying demands placed on different sections of a brake rotor. Temperature and pressure changes across the rotor's surface are major causes of wear, warp, and brake failure. To function optimally, each of the rotor's three functional sections typically requires a material that has a specific combination of strain and thermal properties.
@wb8nbs: The gunmetal gray color of friction ring in the rotor in the picture makes me think that it is probably hardcoat anodized, so it is not just bare aluminum. All other things being equal, I'd expect anodized aluminum to hold up a lot better than bare cast iron. In fact, I'd even expect bare aluminum to hold up better than bare cast iron.
On the other hand, connecting an aluminum brake rotor to a steel wheel hub could be a recipe for galvanic corrosion of the aluminum. Galvanic corrosion between steel hubs and aluminum wheels is also a common problem. In either case, a thick coat of antiseize between the two parts might help to prevent corrosion by galvanically isolating the parts from one another.
I can't wait to see a $500 brake rotor for a $10,000 car. Materials will be 10% of the vehicles value. Can you picture this repair on a 5 year old chevy cavalier or equvalent vehicle? lol, I can't...
There comes a point where practicality and reality need to mix. Cna this be done, sure, but when I can go out and purchase an $80 brake rotor for a 1 ton truck, and instal it myself, I shudder to think what this new material would cost.
Remember when plastic bumpers were supposed to make cars cheaper? yeah... now it costs over $1k to get the stupid thing repainted when some jerk dings you up in a parking lot, where the metal one didn't show the mark in the first place.
Neat idea, but until it's economically feasible, it's a waste of time... much like EV's without gov't subsidation (which still comes from our pocket).
@JimT: According to the brochure on REL's website, the material can only be machined using diamond tooling.
Heat from braking will cause organic brake pads to off-gas. The idea of a dimpled brake rotor is that the dimples provide space for the gases to expand into, supposedly minimizing brake fade. This is the same idea behind cross-drilled brake rotors. The supposed advantage of dimpled rotors over cross-drilled rotors is that a dimple doesn't reduce the cross-sectional area as much as a drilled hole, so the rotor is less likely to crack. (I say "supposedly" for both of these things because I have heard people dispute both of these claims, and I haven't seen any objective data one way or the other).
It's possible to make MMCs using powder processes, but they are more commonly cast (or, sometimes, cast into billets and then extruded). One way to cast MMCs is by stir casting, in which the reinforcement is stirred into the molten aluminum. Another way is by squeeze casting molten aluminum into a fiber pre-form. Based on the brochure, it looks like this is what REL is doing.
@kleetus: I agree with you about cost -- at least for the time being. When I worked on aluminum MMC brakes, it was for military applications, where cost vs. weight considerations are very different than in the civilian market. But a lot of work is being done to find cost-effective ways of producing these materials.
By the way, there is no such thing as a 5-year-old Chevy Cavalier, since 2005 was the last model year for Cavalier. My Chevy Cobalt -- the model which replaced Cavalier -- is more than five years old.
Is there any word on the stopping power Vs. heat buildup on these rotors? I recently went from ceramic pads to metallic pads with new rotors all the way around. There was nothing wrong with my old pads except for stress cracks from the heating and cooling cycle.
@Dave Palmer: Lol... okay, maybe I'm dating myself with a cavalier, but your cobalt would be the same premise. A lower cost vehicle with a significant repair bill for normally wearable items.
Now having the price come down over time I can certainly believe, just look at cmputers, but there are a number of other items, like 'lubed for life' suspension components and u-joints that never lived up to the name, and were just as expensive if not more based on their novel idea that they are 'better'.
I have never had a rotor fail in an automotive disk brake system, but I have had many failures of the caliper mechanism over the years. The reason has been that Chrysler has consistently chosen designs for the caliper assembly that rust and stop sliding where they should. The results have been either brakes that drag and overheat, or brakes that only brake on one side of the disk, resulting in a buildup of an iron oxide material on the inoperative side, which has a much lower friction level, but is far more abrasive to the pads. This failure mode does destry the rotor, but not through any design error in the rotor or material.
The aluminum composite may be a very great improvement, but it would be very handy to find out about it's corrosion resistance to the southeastern Michigans salt brine roadways. If it can stand up to that test, where can we buy these rotors?
Formula 1 racecar brake discs are made from carbon fiber composite.I heard that the coefficient of friction increases as the F1 brake discs heat up, the opposite of cast iron brake discs.
If the automakers aren't taking a hard look at this, I'd be shocked. Cutting 30 lbs from the weight of a mid-size sedan is a gigantic change. Engineers typically fight to cut a pound or two from their vehicles. If they can cut 10 lbs, they're heroic. Thirty is off the scales.
Does anyone know why Carbon brakes are not getting cheaper? After all carbon isn't that expensive a feedstock. How are they made?
They would be much lighter than even this advance with the lower weight advantages in handling and mileage.
Some brakes come with retracting clip springs that pull the pads off the rotor. In every EV I do I always check the brakes and many other drags like diff fluids, new low rolling resitance tires, aero mods, etc which can literally increase range 10-50%!! Or cut the battery pack/cost/weight as much for the same range.
Of course the best brake is one that doesn't have to stop all that excess weight most cars have by designing in lightness, KIS.
The 100-percent solar-powered Solar Impulse plane flies on a piloted, cross-country flight this summer over the US as a prelude to the longer, round-the-world flight by its successor aircraft planned for 2015.
GE Aviation expects to chop off about 25 percent of the total 3D printing time of metallic production components for its LEAP Turbofan engine, using in-process inspection. That's pretty amazing, considering how slow additive manufacturing (AM) build times usually are.
A $1,500, hand-operated, bench-model, plastic injection machine crowdsource-funded via Kickstarter can be used to mold small, quality, plastic parts inexpensively, on demand.
The federal government is launching competitions to kickstart three more manufacturing innovation institutes, including one focused on Lightweight and Modern Metals Manufacturing Innovation.
The airframe of Airbus's A350 XWB consists of a bigger proportion of carbon-fiber-reinforced composite structures than any other commercial jet to date: over 53 percent by weight.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 5
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This radio show will show what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
16 
