diff --git a/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-21T16:36:48,640821636+00:00.png b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-21T16:36:48,640821636+00:00.png new file mode 100644 index 0000000..2ace4b4 Binary files /dev/null and b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-21T16:36:48,640821636+00:00.png differ diff --git a/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-21T17:12:20,117329889+00:00.png b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-21T17:12:20,117329889+00:00.png new file mode 100644 index 0000000..54154c0 Binary files /dev/null and b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-21T17:12:20,117329889+00:00.png differ diff --git a/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T19:57:31,635322986+00:00.png b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T19:57:31,635322986+00:00.png new file mode 100644 index 0000000..925d1ec Binary files /dev/null and b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T19:57:31,635322986+00:00.png differ diff --git a/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:00:59,114434073+00:00.png b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:00:59,114434073+00:00.png new file mode 100644 index 0000000..18d5d7e Binary files /dev/null and b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:00:59,114434073+00:00.png differ diff --git a/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:01:59,453437307+00:00.png b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:01:59,453437307+00:00.png new file mode 100644 index 0000000..20e507b Binary files /dev/null and b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:01:59,453437307+00:00.png differ diff --git a/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:02:42,050513187+00:00.png b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:02:42,050513187+00:00.png new file mode 100644 index 0000000..0aa5d38 Binary files /dev/null and b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:02:42,050513187+00:00.png differ diff --git a/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:31:12,395307966+00:00.png b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:31:12,395307966+00:00.png new file mode 100644 index 0000000..1a572cf Binary files /dev/null and b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:31:12,395307966+00:00.png differ diff --git a/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:32:47,838820599+00:00.png b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:32:47,838820599+00:00.png new file mode 100644 index 0000000..d64f1d2 Binary files /dev/null and b/uni/mmme/1029_materials_and_manufacturing/images/vimscrot-2022-02-28T20:32:47,838820599+00:00.png differ diff --git a/uni/mmme/1029_materials_and_manufacturing/manufacturing.md b/uni/mmme/1029_materials_and_manufacturing/manufacturing.md index bab3f6a..368c574 100755 --- a/uni/mmme/1029_materials_and_manufacturing/manufacturing.md +++ b/uni/mmme/1029_materials_and_manufacturing/manufacturing.md @@ -131,3 +131,50 @@ $$C = \frac{mC_m}{1-f} + \frac{C_t}{n} + \frac{1}{\dot n} \left[ \dot C_{oh} + \ - Low thermal capacity and high conductibity - Low solubility - Not contaminated by air + +## Deformation + +When a metal is plastically deformed, dislocations move and multiply. + +Annealed aluminium may have a dislocatio density of around 200 m per mm$^3$. +This is a very low amount. +A heavily cold worked piece may have a density of up to 270 km per mm$^3$. + +As dislocation density increases, the dislocations impede the motion of other dislocations. +This means that to continue plastically deforming, more stress has to be applied. + +The stress goes down towards the end of the graph due to the material necking, meaning the +material gets thinner. +This means that the engineering stress is lower as the true area is lower. +The true stress, however, is going up: + +![](./images/vimscrot-2022-02-28T20:01:59,453437307+00:00.png) + +### Effect of Prior Deformation (*Work Hardening*) + +![](./images/vimscrot-2022-02-28T20:02:42,050513187+00:00.png) + +See +[here](materials.html#work-hardening-and-cold-working) +for more information + +### Effect of Temperature (Diffusion) + +In an alloy, atoms tend to migrate from regions of high concentration to low concentration. +This is diffusion. + +More information on diffusion [here](materials.html#diffusion). + +### Annealing + +Annealing is a process by which a component is heated to reduce work hardening. + +![](./images/vimscrot-2022-02-28T20:32:47,838820599+00:00.png) + +These are diffusional processes and only occur at higher temperatures. + +When the temperature of a material, $T > 0.55T_m$, it is said to be hot. +A material being worked on hot has its deformations eliminated as fast as they are created. + +A material is said to be cold when $T < 0.35T_m$. + diff --git a/uni/mmme/1029_materials_and_manufacturing/materials.md b/uni/mmme/1029_materials_and_manufacturing/materials.md index e0689f1..1e8f991 100755 --- a/uni/mmme/1029_materials_and_manufacturing/materials.md +++ b/uni/mmme/1029_materials_and_manufacturing/materials.md @@ -27,17 +27,17 @@ tags: [ uni, nottingham, mechanical, engineering, mmme1029, materials ] usually associated wit structural and mechanical properties or long standing chemical effects like corrosion: - - fossil fuels - - hydroelectric - - oil from shale and tar - - sands - - coal gasification - - liquefaction - - geothermal energy - - wind power - - bomass conversion - - solar cells - - nuclear reactors + - fossil fuels + - hydroelectric + - oil from shale and tar + - sands + - coal gasification + - liquefaction + - geothermal energy + - wind power + - bomass conversion + - solar cells + - nuclear reactors ### Applications of Energy-Related Materials @@ -1140,7 +1140,74 @@ You can apply the Arrhenius equation for all thermally activated diffusion: $$D = D_0 \exp{\left( - \frac{Q}{RT} \right)}$$ -where $Q$ is the activation energy and $R$ is the ideal gas constant (8.31 J k$^{-1}$ mol$^{-1}$). +where $D$ is the diffusion coefficient, $D_0$ is the frequency factor, $Q$ is the activation energy, +$R$ is the ideal gas constant (8.31 J k$^{-1}$ mol$^{-1}$). + +You can find the diffusion distance, $x$, with the following equation: + +$$x ~ \sqrt{Dt}$$ + +![](./images/vimscrot-2022-02-28T20:31:12,395307966+00:00.png) + + +# Materials in Sustainable Transport + +- Concerns over use of fossil fuels, climate change +- Const of energy +- Energy use in making and moving vehicles +- Rising energy prices mean cost of fuel is comparable to cost of car +- 1/4 of energy used in UK is to transport goods and people +- Legislation and voluntary targets set by EU to improve fuel efficiency +- In 2015 average CO2 emmisions as 130 g / km +- Engine powerhas gone up significantly from 2001 to 2018 (~30%) yet engine displracement has gone + down ~10% and CO2 emissions down ~18% while weight has gone up ~10% + +## Is the car emissions reduction target significant? + +Overall CO2 emissions in 2016 is 466 Megatonnes. + +Does a reduction from 130 g / km to 95 g / km (a 35 g/km reduction) make a significant difference? + +There are 33 million registered cars in the uk. + +If they average around 8000 miles each (~13000 km) per year that's a ~15 Megatonne reduction, +or about 3% of the annual C02 emmissions, a significant reduction. + +## Materials in Cars + +- Most of the energy used by cars is during driving (71%) +- This means the mass of the vehicle has a great effect on its emmissions across a lifetime +- The body, suspension, drivetrain, and interior all contribute roughly a quarter to the mass of the + car +- However, the mass of cars are increasing + +### Material Substitution + +- The material will likely have performance requirements: + + - It may need to be a physical size + - It may need to operate at certain temperatures + - It may need to bear a certain load + +- The component mustalso be designed for convenient manufacturing, assembly, servicing, disposal, + remanufacturing and/or disassembly + +#### Case Study --- 2012 Honda Accord + +- Body --- opted to stay with steel --- aluminium intense and multi-material approaches were both + rejected due to higher costs and limitations in manufacturing and assembly. + Recyclability was also noted as an issue due to different grades of aluminium needing to be + separated at end of life. +- Doors and bonnets --- move to aluminium from steel --- more costly but the mass savings made this + option worth it +- Wiring --- aluminium to copper --- lower mass for same conductivity, copper is more expensive + (I think) +- Seats --- steel to composites or magnesium structural components --- very high weight savings + +## Choosing a Material + + + # Glossary