OIM Analysis Tutorials

Insert Generated Table of Contents here OIM Analysis Tutorials TOC \o "1-3" \h \z Basic Tutorial 2 Step 1 – Loading dataset 2 Step 2 - Creating Maps 4 Step 3 - Grains in OIM 9 Step 4 - Discrete PF and Rotation 13 Step 5 - Texture 17 Step 6 - Templates 20 Highlighting and Partitioning 24 Introduction 24 Manually Isolating Lath Areas 25 Step 1 - Load File 25 Step 2 - Create IQ/Phase Map 26 Step 3 - Configure Highlighting 28 Step 4 - Highlight Alpha Grains 28 Step 5 - Create Lath Partition 29 Characterizing Boundaries 29 Step 1 - Create MDF 30 Step 2 - Reconfigure Highlighting 31 Step 3 - Discrete MDF Highlighting 32 Step 4 - Boundary Specifics 33 Automated Highlighting 38 Step 1 - Grain Size Chart 38 Step 2 - Chart Highlighting 40 Step 3 - Partition Formula 40 Misorientation Profile 43 Step 1 - Highlighting Configuration 43 Step 2 - Profile Analysis 43 Twins Tutorial 45 Introduction 45 Step 1 - Getting Started 46 Step 2 - Cleanup 47 Step 3 - Isolating the IC Lines 51 Step 4 - Twins 55 Step 5 - Coherent Twins 60 Basic Tutorial Step 1 – Loading dataset The following tutorial should help you get started with OIM Analysis as well as show some of the analytical procedures a researcher might use for investigating the crystallographic structure of a polycrystalline material. For this tutorial, we will be using a dataset obtained from rolled aluminum sheet for a friction stir welding application. This dataset is installed during the OIM Analysis installation procedure. Assuming the defaults were selected during the installation procedure, this data file is most likely located in Program Files/TexSEM/OIM Analysis 4/Samples. To get started launch OIM Analysis. The first step is to create a new project. The easiest way to do this is to left-click the Quick New button on the QuickGen Toolbar and select Project from the pop-up menu as shown below. This will create a default project. (there are multiple ways to open project, this is true with many functions in OIM so that users can operate the software in the way that is most convenient - projects can also be created from the New Project button on the Standard Toolbar or using New Project from the File Menu.) The next step is to add a dataset to the project this is done by clicking on the project icon in the project tree with the right hand mouse button. Select New>Dataset from the pull down menu as shown below. You will now be prompted to open the file containing the dataset as shown below. Select the file FSW Al.osc. Once the file is successfully opened the screen should look something like that shown below. In the project tree window you will see the project, dataset and partition. The partition was automatically created and contains all of the data in the data set. A window providing some summary information on the dataset will be displayed when the dataset is opened. Step 2 - Creating Maps We will now create an inverse pole figure map. This is most easily done by pressing the IPF Quick Map icon on the QuickGen Toolbar as shown below. This should result in the screen appearing as below. The inverse pole figure map is color coded map where the color gives an indication of the crystal direction aligned with the sample normal. For example, in this case, the points colored blue have <111> directions aligned with the sample normal, the points in red are <100> oriented and the points in green are <110>. It should be noted that in this map, only the crystal direction parallel to the sample normal is fixed. The in-plane orientation is not indicated in this map. The orientations can be confirmed by switching to Lattice in the Information Pane of the window as shown below. As the cursor moves around the map, a wire frame schematic of the crystal is displayed. Now, let's create a second type of map using an alternative approach. On the project tree click on the Partition (a Partition contains a filtered subset of the data - in this case it contains all of the data) entitled All Data with the right mouse button. This will bring up a pull-down menu. Select New>Map from the menu as shown below. This will display the Map Properties dialog. This dialog allows the map to be configured. In this case, we want to create an Image Quality (IQ) map overlaid with low and high angle boundaries. To do this we set the Map Grayscale Type to Image Quality. We then need to set the Grain Boundary Type to Rotation Angle and press the Add button to configure the low angle boundaries to be displayed. Pressing the Add button bring up the following Add Boundary dialog. We will define "low angle" boundaries as boundaries with misorientation between 1 and 15 degrees as shown. We want to assign a specific color to these types of boundaries. This is done by hitting the Segment tab in the dialog. In this page of the dialog the color and thickness of the boundary segments can be defined. Make these types of boundaries yellow as shown. Close the Add Boundary dialog by pressing the OK button and hit the Add button again in the Map Properties dialog to configure the high angle boundaries. In this case, define the "high angle" boundaries as boundaries with misorientations exceeding 15 degrees and set the color to blue. Once the boundaries are configured they should be listed in the Map Properties dialog as shown below. After the OK button is pressed in the Map Properties dialog, the following map will be generated. The window has been maximized to show more detail. Note in the legend for the map the fraction of the low and high angle grain boundaries. There will also be a note defining the Minimum Boundary Misorientation for calculating fractions. The default is 2 degrees, however, we have defined low angle boundaries as boundaries with misorientations lying between 1 and 15 degrees. To change the minimum boundary misorientation select Preferences from the Settings menu. This will bring up the Preferences dialog. Set the Minimum Boundary Misorientation to 1 for this example. This will result in more boundaries being shown in the map. Step 3 - Grains in OIM Grains have a well defined meaning in OIM, however, the definition differs from that used in tradition metallography. In OIM, two neighboring scan points belong to the same grain if the misorientation between them is less than some value prescribed by the user - the Grain Tolerance Angle. This means, that two neighboring points in a grain may differ in orientation by 0.1 degrees, but the misorientation between points at one end of a grain and the opposite end may differ considerably more. This is especially true in deformed materials like the rolled aluminum used in this tutorial. The best way to see how the points are grouped into grains is to use a Unique Grain Color Map. In this map, each grain is assigned a color. The colors do not denote an orientation, the grains are simply colored to distinguish them from neighboring grains. To generate a Unique Grain Color Map, select a Grain Map from the QuickGen Toolbar. This will produce the following map. In order to understand the parameters used in constructing the map, click on the All Data partition in the project tree with the right mouse button and select Properties from the pull-down menu. This will bring up the Partition Properties dialog. Switch to the Grain Size page of the dialog by hitting the Grain Size tab. Note the default value of 5 degrees misorientation for the Grain Tolerance Angle and a value of 2 for the Minimum Grain Size. The minimum grain size defines the number of scan points before a group of neighboring and similarly oriented points is identified as a grain in the OIM software. In order to illustrate the impact these parameters have on the Grains in OIM, we will create a new partition. This is done using the right mouse pull down menu at the dataset level as shown below. Once again, the Partition Properties dialog will be displayed. Switch to the Grain Size page and change the Grain Tolerance Angle to 15 degrees. Close the dialog by pressing on the OK button. This will add a new Partition to the Dataset. This is indicated in the Project Tree. The name of the two partitions can be changed to reflect the differences the the Grain Tolerance Angle. This can be done using the right mouse activated pull-down menu and selecting Rename. With the new partition active (activate it by simply left-mouse clicking on it), create a new Unique Grain Color Map using the QuickGen Toolbar. Now we can compare the resulting maps. To display the maps as shown here, close all of the windows except the two grain color maps and then hit the Tile Vertically button on the Standard Toolbar. Note the larger grains in the map with 15 degree tolerance. While it should be recognized this is a relatively small area scan to keep the file size small for the tutorial, we want to look at Grain Size Distribution. Before starting this process we need to make some more changes to the Grain Size page in the Partition Properties dialogs for both partitions. Because the grains are elongated many of the grains touch the edges of the scan area. In general, these are excluded from any kind of statistical analyses like Grain Size Distribution. However, because our sampling area is small we need to include these scan edge grains. Open the Partition Properties dialog for each partition by selecting Properties from the pull-down menu for each partition. Check on the "Include grains at edges of scan in statistics" option as shown below. Now we will create a chart showing comparing the Grain Size Distribution for each partition. This is done using the pull-down menu at the project level and selecting New>Multichart. This will bring up the Multichart Dialog. The type of chart needs to be selected as shown, and a chart added for the two partitions. This is done by pressing the Add button to bring up the Multichart Entry dialog where the partition can be selected. Name is the name used in the chart legend. The resulting chart should appear as follows. Even with the small sampling of grains, it is clear that setting the Grain Tolerance Angle to 15 degrees produces more large grains, whereas a value of 5 degrees produces smaller grains. Step 4 - Discrete PF and Rotation In this step of the tutorial we will begin to look at the orientations themselves with respect to the sample. The sample was obtained from rolled aluminum sheet used for friction stir welding. The sample scanned was sectioned from a plane normal to the rolling direction as shown in the schematic below. One of the most common tools for visualizing orientations in polycrystalline materials is the pole figure. Before plotting a pole figure close all of the document windows. Generate an IPF map from using the appropriate button on the QuickGen toolbar and plot a pole figure. The pole figure is most easily generated by simply hitting the Pole Figure button on the QuickGen Toolbar. This will automatically generate a 001 pole figure. However, for FCC rolled materials, the most common pole figure displayed in the literature is the (111) pole figure. We want to change the (001) to a (111) pole figure. This is easily done by clicking in the pole figure with the right hand mouse button and selecting Properties from the pull-down menu. In the resulting Pole Figure dialog, change the pole figure to an (001) pole figure by double-clicking on the (001) pole figure in the list. The resulting pole figure should appear similar to that shown below. However, this doesn't look like a typical (111) pole figure for rolled aluminum. This is because of the plane on which the scan was performed. Pole figures from rolled materials are more typically obtained from a plane as shown in the following schematic. In order to get the data into this configuration we need to rotate it 90 degrees about the transverse direction or TD. This can be accomplished by selecting Rotate from the Dataset pull-down menu in the project tree. The Rotate dialog will be displayed. We want to rotate 90 degrees about TD in a negative sense. We can rotate the data, creating a new dataset within the project or simply rotate the data in place. For this example we will rotate the data in place. The change in orientation will be reflected immediately in the pole figure and the IPF map. The map and pole figure should appear as follows. The pole figure looks much more like that expected for rolled aluminum. However, it is clearly not exactly centered. This is likely due to tilts introduced during the sectioning or subsequent sample preparation. Successive rotations of -1 degree about ND, 4.5 degrees about TD and -3 degrees about RD seems to work well. (One way to identify the amount of rotation needed is to use Highlighting in Plot Misorientation Mode in the pole figure.) The pole figure should appear as follows after these finer rotations. Step 5 - Texture While the discrete pole figures give a general impression on the clustering of orientations in orientation space, they are not very quantitative. For quantitative information on the orientation distribution we need to use the tools of Texture Analysis. OIM Analysis has many tools for characterizing the textures of polycrystals. In OIM 4 the texture analysis is contained within a Texture Document at the same level in the project tree as the maps, charts or discrete plots. The Texture Document contains all of the calculation parameters and resultant data needed to generate texture plots such as pole figures or ODFs. The actual texture plots are maintained at a level below the Textures themselves. To calculate a texture select New>Texture from the Partition pull-down menu. The following Texture Properties dialog will be displayed. First we need to select the calculation method and associated parameters by hitting the Edit>> button. This will display the following dialog. In this case, we will simply use the default values for now. We want to compare the discrete (111) pole figure already plotted against one derived from the texture calculations. This is done by pressing the Add PF button on the texture properties dialog. This will bring up the following dialog. The (hkl) should be set to (111). Once all of the dialogs are closed using the OK buttons, the texture calculations will commence. For this file, this should only take a couple of minutes. When the calculations have completed an icon representing the texture is included into the project tree. To generate the pole figure plot, right-mouse click on the new texture in the project and select New>Texture Plot from the pull down menu. The (111) pole figure should already be selected and ready to display. Once the OK button is pressed the pole figure will be generated. Step 6 - Templates It may take a considerable amount of effort to get all of the partitions, textures, plots... configured precisely as desired. OIM Analysis has several features that make it possible to reuse the configurations developed during an analysis session. For example, a pole figure can be copied from one data set to another, this doesn't mean the actual pole figure plot is copied but rather the plot is generated using the data from the new dataset and the parameters from the old pole figure. As an example, let's construct a map showing the fraction of material within 10 degrees of the "S" orientation (this is a specific orientation, {123}<63-4>, that is frequently observed in rolled FCC materials). This is done by going to the dataset icon in the project tree and selecting New>Map from the pull-down menu. Select Crystal Orientation for the Color-Coded Map Type and Image Quality for the Gray Scale Map Type from the resulting Map Properties dialog. Now press the Edit>> button for the Color Coded Map Type. This brings up the following dialog. First turn on the orthotropic (rolled sheet) symmetry as we are looking at a rolled aluminum sheet that exhibits strong processing symmetry (the pole figure is symmetric about the horizontal and vertical axes). Press the Add button to set the software to look for the "S" orientation as shown below. (You only need to enter one set of orientation angles/indices) Once these parameters are all defined, the resulting map should appear as follows. The colored points are those, which have "S" Orientations. The map legend indicates that the volume fraction of the "S" component is 33%. Now open a new dataset (use FSW Al 2.osc), apply the appropriate rotations. Use the copy document function and paste the map into the new dataset. This should result in the following. The map definition can also be saved as a Template and applied during later analysis sessions. To save the template use the Export>Template function from the pull down menu on the project tree or in the map window. This template can then be applied at a later time using Apply Template at either the Partition, Dataset or Project levels, the template will be applied to all partitions in the dataset when applied at the Dataset level and in all datasets when applied at the Project level. As an example, a template containing a more extensive set of analyses for rolled fcc materials is included with the OIM 4 installation. Apply this template to the FSW Al 2 dataset. This will result in a new partition being created with a Crystal Orientation Map for several orientations as well as a Crystal Orientation chart showing their distribution as a function of tolerance angle. In fact, templates can be attached to user specified buttons in the QuickGen Toolbar using the Preferences dialog under the Settings menu making a whole set of analyses tied to a single push of a button. Highlighting and Partitioning Introduction This tutorial will use OIM scan data from dual phase titanium sample. The sample has large grains of alpha titanium and a lath structure composed of both alpha and beta titanium. The tutorial consists of four parts. 1 Opening the file, creating a combined image quality and phase map, using manual highlighting on the map in grain mode to create a partition containing the lath area. 2. Operating in the lath partition, identify the character of the interphase boundaries using the Discrete Axis/Angle Misorientation. 3. Use an alternative (more automated) method based on the grain size chart to isolate the lath areas. 4. Use the misorientation profile highlighting function to characterize the internal structure of the large alpha grains. This will also introduce the user to the interactive view properties. In the process the tutorial introduces many aspects of OIM Analysis including: Loading scan data. Creating maps. Overlaying boundaries on maps (axis/angle type) Highlighting in maps. Configuring the highlighting gradient. Setting the highlighting mode. Using the grain highlighting mode. Using the vector profile highlighting mode. Recording highlighting data in a tabular list. Configuring the recorded highlighting table. Exporting the recorded highlighting table. Partitioning By highlighting in maps. By highlighting in charts. Using an explicit formula. Creating a Discrete Misorientation Plot using the axis/angle representation Highlighting in discrete plots Configuring discrete plots Zooming in on maps Using the Flexiview Tab Creating a Grain Size Chart Highlighting charts Manually Isolating Lath Areas Step 1 - Load File tc "Step 1 - Load File"xe "Step 1"Assuming OIM Analysis has just been launched and that no project has yet been created, the easiest thing to do is to open the scan data file. This is done by selecting Open from the File menu. This results in the following dialog being displayed. Set the file type to OIM Scan Files (*.osc). Open the file entitled "Dual Phase Titanium.osc". When the file is opened it will be automatically placed under a new project in the project tree.. In addition, 3 partitions will be created under placed under the data set in the project tree. One partition containing all points within the scan data, one containing only those points identified with