material structure Solid Works

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1ME2341Laboratory OneSolid Works Module Revised January 2015

Metal Crystal Structures in Solid Works and 3D Printing

Lab Module

1. Summary

As we have discussed in this course, there are several different crystal structures, only a small fraction of

which are covered in this class. One challenge in analyzing such structures is in visualization; manyconcepts including symmetry, interstitial space, diffusivity and close-packed planes/directions all dependon our ability to see and assemble 3D ordered structures. Typically, our approach in materials scienceinvolves drawing ball-stick models, or building models in the lab. In mechanical engineering, 3Dvisualization is crucial for several aspects of design, and modeling software is available to conceive and

present our ideas. Accordingly, the purpose of this is to combine the above two objectives, by leveragingMechanical Engineering-based modeling skills in SolidWorks to improve knowledge of materials scienceconcepts. We ask each student to do this part of the lab as individuals rather than in a group, as these areskills that would creatively add to any CO-OP portfolio. Follow the included steps, and if you have extratime, try and create these models in more than one way. Solidworks is a powerful tool, and there is

usually more than one method to accomplish any task. The Materials Science topic for this lab iscreating metal crystal structures and this will include BCC, FCC, and interstitials. Absolutely no prior

knowledge of SolidWorks is required to complete this lab module.

2. Tasks

2.1. Create the BCC Crystal Structure

Follow the directions listed on the Creating a BCC Crystal Structure Guide included in the LabMaterials.

2.2. Create the FCC Crystal Structures

With what you know now, create the FCC Crystal Structure.

2.3. Insert an interstitial atom (Mind the gap!)Smaller interstitial atoms can be driven into the gaps within these metallic structures (such as carbonatoms diffusing into iron structures to make steel). Lets investigate how much space there really is. Saveyour BCC and FCC crystal structures as new files. Insert a single interstitial atom into the tetragonalinterstitial of each structure. Generate additional files and instead insert the interstitial atom into the

octahedral interstitial. Make these atoms as large as they can be without overlapping the metal atoms.

2.4. Characterize your structures

a. Include a Screen Shot of the structure you created. Note: Make the unit cell wire framed to guide the eye.b.

Show how you calculated the lattice parameter?c.

Which is the Most Packed Plane in Miller-Bravais? Include a visual of the cross section of this

plane that clearly shows the atoms touching.d. What is the APF? Show Calculation.

e.

Take two screen shots showing the placement of the octahedral and tetrahedral interstitial atoms.

2.5. Generate an .stl file that can be used to 3-D print your structures

Follow the directions on How to 3-D print your structure.Note: You can send your file to Snell Library forprinting.

2.6. Generate your individual 4 page report submission

Page 1Title page that has your name, lab section and your best graphic.Page 2Entitled BCC structure. Contains the five characterizations (a-e) for the BCC Structure.Page 3Entitled FCC structure. Contains the five characterizations (a-e) for the FCC Structure.


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Page 4Some images and a brief description of your final .stl code geometry.

Note: Everybody has to turn in his/her own Solid Works report. The due date and the turn-in

location is the same as for the Lab 1 Group Report. Only one copy of the Solid Works Report is

required.

3. Creating a BCC Crystal Structure Guide

3.1.Load Solidworks 2012

3.2.Creating your First Atom

Included in the lab is a page entitled, Creating an Atom. Follow the steps carefully, and for

simplicity sake, ensure that the center of the atom is the origin. Make the radius 1.26 (correspondingto the 1.26 angstrom actual radius for BCC Iron).

3.3.Creating your Unit Cell Guide

The next step is to create your unit cell template. This will be a framework of where all of the atoms

will go, making it easier to place the atoms in the correct place at the assembly level. In the lab thereis a page entitled, Creating a Unit Cell, you should follow those steps carefully up until Step 5.

Make the lattice parameter 2.87 (corresponding to the 2.87 angstrom actual lattice parameter of BCCIron).

3.4.Creating your Custom Reference Lines

Like most of the unit cells you will be creating the BCC Crystal Structure has 8 corner atoms. This is

why creating the cube guide works best, as there is a reference point in each of the 8 corners. Thecharacteristic that makes the BCC unique is the central atom. This central atom is located in the exactcenter of the cubic unit cell, allowing for the atom to make contact with the corner atoms along the

body diagonal. To create a reference point at this location, make sure that your unit cell created instep 3 is still open.

a. Create a Plane along the Body Diagonal

In the CommandManager, under the features tab, select Reference Geometry


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about two thirds of the way down, then locate your Unit Cell you just created. Click it and then placeit towards the center of your screen.

b. Adding Atoms

First off change the view to wireframe, as this Unit Cell is nothing but a guide. You only want tochange the unit cell to wireframe so right click it in the assembly tree, go to ComponentDisplay cut >

extrude.

Select a plane and cut the around the unit cell, as shown below. You may need to extrude from themid-plane to achieve a clean cut.

3.9.Make one final cut in a plane perpendicular to step 8. Save the BCC unit cell as a .sldprt file, make tocheck the save all components option.


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3.10. Open the .sldprt file and re-save as a .stl file.

3.11.

Using the 3D Printing Lab(Not Required)The media lab on the second floor of the library is agreat resource for additive manufacturing and 3D Printing. If you are interested in getting your .stl

files printed, fill out an order form here: http://dmc.northeastern.edu/help/order-form-3d-prints.You

can upload the .stl and the media lab will notify you when your part is finished! For moreinformation on the 3D printing lab at Northeastern, check out their website:http://dmc.northeastern.edu/abilities/3d-printing.This service costs a little bit of money dependingon your print size so be aware of this before printing. The choice and cost is up to you. 3D printing

is a great resource to keep in mind when your Capstone projects come around.

4. Creating an Atom

4.1.

Create New File

Load Solidworks 2012, select File


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The work area should be loaded now, and the next step is to create an arc which can later be revolvedinto a 3D sphere. Begin by defining your sketch plane, select Front Plane, which is located in a pane

on the left side of the screen. Next select Insert


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Select Linefrom the CommandManager. The next two clicks will be the beginning and ending pointsof the line. Seeing as the goal is to close off the arc, make those two points the beginning and end of

the arc.

4.5.

Dimensioning

Select Smart Dimensionfrom the CommandManager Pane. Next select the arc, and click to dragyour newly added dimension to any location on the screen. Immediately after, the modify dialogue

box will appear, displaying your current radial dimension. When finished the Dimensioning Pane will

appear on the right side of the screen, giving you a second opportunity to make adjustments, feel freeto click the Green Checkmarkat the top to clear it away. Finally click Exit Sketchin the

CommandManager.

4.6.

Revolution


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Immediately after closing out the sketch pane, the left pane should change to the Revolve Menu. Thepane will be almost entirely filled out, only requesting for the Axis of Revolution. This will be the

line which was drawn to close the arc. Select the box to the right of the Axis of Revolution, and it willhighlight blue, and then click the line. The box should then populate itself. Solidworks will show youan example of what the sphere will look like, select the Green Checkmarkwhen satisfied.

4.7.

Save

Select File


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5.2.

Create Initial Sketch

With the initial plane selected, go to the top menu bar and chose Insert


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5.4.

ExtrudeOnce exiting the sketch menu, the right panel will immediately change to the Boss-Extrude menu.You will also see the rectangle which was just drawn made 3D with a default extrusion value. Change

that value in the Depth Box to that of the lattice parameter and then click the Green Checkmark toaccept the extrusion.

5.5.

Creating Extra Reference Lines

It seems to be the easiest to create extra reference geometry in the unit cell to make placing the atomseasier later. For example if you have a BCC crystal, there is one atom which lies in the center of the

body diagonal plane. If you create a point in this position in the unit cell, arranging the structures in


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the assembly level becomes as easy as making two points coincident. To do this see the ReferenceGeometry Page in your packet, or see the Creating a BCC Crystal Structure Guide.

5.6.Save your unit cell

Remember to constantly save your work File

material structure Solid Works

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