Load:5–500mN

Thermal drift correction

Temperature range: 20C–800C

Atmosphere: Air or argon

Our group often works with powdered materials, and we maintain the safety protocols and equipment to handle powder safely.

TechCut 4™ Precision Low Speed Saw

The TechCut 4™ is a precision low speed saw used for the sectioning of small and delicate samples. The saw is most used to section material from tensile samples for subsequent microstructure characterization.

Specifications:

            Variable speed with LED display:          10-500 RPM (10 RPM increments)

            Micrometer sample indexing:                0-25 mm range (0.002 mm resolution)

            Variable sample loading:                       0-300 grams

            Cutting capacity:                                   2” (51 mm) thickness

TechPress 3™ Mounting Press

The TechPress 3™ is used to mount material for metallographic sample preparation. The operator can choose to input a program manually or choose a program from a database of 80 preloaded, adjustable parameters for mold size, single mount or duplexing, mounting resin, curing time and temperature, cooling time, and pressure.

Specifications:

            Selectable units:                        psi/BAR and °C/°F

            Molding pressure:                     up to 4500 psi (310 Bar)

            Heat power:                              1500 W

Curing temperature:                  0-200°C (32-392°F)

Curing time:                             0-100 minutes

Cooling time:                            0-100 minutes

MultiPrep™ Polishing System – 8”

The MultiPrep™ is a semiautomatic system that allows for precise sample preparation using the front (sample advancement) digital indicator to display real-time material removal and the rear (static) digital indicator to display absolute vertical position. Dual micrometers (pitch and roll) can be used to control the angular positioning head to allow for parallel polishing, angle polishing, site-specific polishing, or any combination thereof.  

Specifications:

            Digital indicator resolution:      1 μm (sample advancement and static)

            Dual axis micrometer:               +10° / -2.5° range (0.02° increments)

            Variable sample load:                0-600 g (100 g increments)

            Variable platen speed:               5-350 RPM (5 RPM increments)

            Automatic sample rotation:       8 speeds (full or limited)

M-Prep 5 ™ Grinder/Polisher (2)

The M-Prep 5™ is a grinding/polishing system that is used for manual metallographic sample preparation. The magnetic platens and PTFE support discs allow for greater versatility of grinding and polishing operations for a single system.

Specifications:

            Variable speed with digital display:                    10-500 RPM (10 RPM increments)

            Platen diameter:                                                8” or 10”

MetPrep 4™ PH-6™ Grinder/Polisher with Power Head

The MetPrep 4™ is a semiautomatic sample preparation system that allows for up to 25 programmable steps for maximum versatility. The PH-6™ power head can prepare up to 6 samples simultaneously when operated in individual force (IF) mode and up to 12 samples simultaneously when operated in central force (CF) mode.

Specifications:

The following setting can be individually adjusted in each of the 25 steps:

            Platen RPM:                 50-400 (10 RPM increments)

            Mode:                          Complimentary/Contradictory

            Time:                           0-120 minutes (15 second increments)

            Sample RPM:               0-150 (10 RPM increments)

            Force:                           Individual/Central (adjusts force value accordingly)

            Force:                           LbF (pound-force) or N (Newton), selectable units

                                                Central: 5-90 LbF (1 LbF increments) or 22-394 N (~4 N increments)

                                                Individual: 0-22 LbF (1 LbF increments) or 0-96 N (~4 N increments)

            Fluid:                           Off, Water, AD-5™ (fluid dispenser)

            Rinse:                           0-60 seconds (1 second increments)

            Friction Reduce:           On/Off

            Reduce Time:               0-60 seconds (1 second increments)

            Reduce %:                    0-90 (10% increments)

            Friction Start:               On/Off

Developed within the group and in collaboration with other groups.

The seminal work of D.J.C. MacKay, who incorporated Bayesian statistics and developed practical backpropagation modeling, served as the precursors to this approach and our efforts. H.K.D.H. Bhadeshia built upon and worked directly with MacKay to study complex problems involving metallic materials. R.J. Grylls then began conducting limited investigations of the effects of single input variables on an output, publishing after he joined H.L. Fraser’s research group. Fraser et al., also aided initially by MacKay, Grylls, and Bhadeshia, began to conduct research into applying artificial neural networks for complex physical processes in metallic materials, defining these assessments of a single variable on an output as “virtual experiments,” which permitted a well-trained neural network to be probed to determine the influence of one variable on a physical property while all of the other potential independent variables were artificially held at their average values. During this time, Fraser and Collins understood that these virtual experiments were slices through an n-dimensional hyperspace, and it became obvious that the lower dimensional slices could be described using simpler functions than the full neural network, a domain-specific recognition of the manifold hypothesis. Following this prior work, with the assumption that a mapping was possible between the basis vectors of the n-variable hyperspace equally represented by the expansion of terms of an artificial neural network and the basis vectors representing the physical processes, Ghamarian and Collins sought to establish a constitutive equation for the room temperature yield strength of a titanium alloy given variations in its compositional and microstructural states. They applied a hybrid artificial neural network-genetic algorithm method that optimized the unknowns in a postulated physically-based equation, testing the optimized physically-based model against slices through a hyperspace function representing the neural network model and the data. This latter effort was quite inefficient, but resulted in a physically-based equation that was demonstrated, in subsequent work, to be generalizable to multiple processing and compositional variations.

Abaqus

Finite–Element Modelling (FEM) software package initially developed in 1978 by D’ASSAULT Systèmes. Often considered the ‘gold–standard’ of FEM packages and known for its highly customizable andgeneral–purpose nature. Capable of explicit, implicit and frequency based solutions.

COMSOL Multiphysics

Finite–Element Modeling (FEM) software package developed in 1986. Known for the ability to solve weak–form differential equations and unit–aware architecture. Extensible through Java and MATLAB APIs. Also highly customizable through APIs and various physics modules that are available (electromagnetics, structural mechanics, acoustics, fluid flow, heat transfer, and chemical engineering).

We have used FEA-based modeling and simulation for multiple problems, including: time-dependent thermal histories of additive manufacturing, ultrasonic fatigue testing of small beams, and Eddy current analysis of signals of near-surface porosity.

Electric furnace

Sand casting capabilities and ancillary equipment

Investment castinc capabilities

The foundary was in a state of disuse when we came in. As part of a safety upgrade to the facilities, we replaced an older gas furnace with the modern electric furnace. The work space is “hot work” certified, and has a welding station, sand boxes, a muller, and various molds. We regularly conduct aluminum wedge castings to teach the effect of solidification rates on the resulting microstructure, dendrite size, and porosity size/fraction.

Ney Vulcan 3-1750 Box Furnace with Programmable Controls (2)

The Vulcan box furnaces can be used to conduct traditional heat treatments with user defined heating and cooling rates and temperature set points. A programmable controller with 9 three-stage programs (6 segments each) and one program with a single temperature hold allows for a wide range of heat treatment applications.

Specifications:

            Temperature range:                   50-1100°C (1°C resolution)

            Temperature accuracy:              +/-5°C at steady state

            Temperature rates:                    0-40°C/minute (positive and negative, 0.1°C resolution)

            Hold time range:                       0:00-99:59 (hours:minutes, 1 minute resolution)

            Internal dimensions:                 12.5” x 14” x 10” (D x W x H)

Custom Atmosphere controlled vertical drop furnace

Atmosphere controlled, programmable, with a externally trigger to drop the sample, plunging it into a quench capability.

Maximum Stroke: 100 mm

Maximum Stroke Rate:2,000 mm/sec

Minimum Stroke Rate: 0.001 mm/sec

Maximum Force (compressive): 20 tons (metric)

Maximum Force (tensile): 10 tons (metric)

Maximum specimen size: 20mm diameter

Maximum Temperature: 3,000°C

Maximum Heating Rate: 10,000 °C/sec

Maximum Quenching Rate: 10,000 °C/sec

The Gleeble was with our research group at Iowa State almost from day one.  It was one of a few capabilities that we knew would form the foundation of our group.  We knew of its capabilities to permit the very precise control of thermal (and thermomechanical) history under controlled environments, which would be enabling for our extensive work with titanium alloys. This capability would be essential for us to conduct relatively rapid processing to set a range of microstructures that could then be tested, permitting us to explore the composition-microstructure-property space.  However, soon after arriving, we were able to conduct another type of test: thermal gradients and so-called bi-combinatorial studies, where composition could be varied along one axis and a thermal gradient along an orthogonal axis. In this manner, we are able to shrink the number of tests required for developing time-temperature-transformation plots.

We are building two systems.  

SRAS integrated into the Robo-Met.3D™:

• Supply: 110V/2ph
• Bespoke inverted imaging system
• THORLabs MLS203–1 High Speed Scanning Stage (110x75mm)
• ZABER LSQ Slides (600mm/300mm) for sample shuttle
• Typical Z–Resolution: Set by Robo–met.3D™
• Typical XY Resolution: 100um/px (scan direction) x 0.1, 0.25, 0.5 mm/px (step direction)
• Coherent Genesis MX (532nm TEM00) and Helios(1064nm <1ns Q–Switch) Lasers
• High speed physical knife–edge detector (<500MHz) 

Gantry-style SRAS system:

Under development

In 2016, while at an AFRL/FAA working group meeting on cold dwell fatigue, and wrestling with needing th analyze the orientation of grains over very large areas for another program on large-volume additive manufacturing, I wondered whether it would be possible to be possible to use Surface Acoustic Waves to back out crystal orientation spatially. After a moment or two of looking, I realized the team at the University of Nottingham had already achieved this, and, fortituously, folks familiar with the team were sitting next to me, and others in the room were aware of potential technical challenges of this emergent technique. A few hours and emails later, and we were on our way to writting our first proposal to bring the technique to the Western Hemisphere.

We are delighted to have found scientific friends through our interactions and collaborations with the team at the University of Nottingham.

Laser: 100W continuous wave

Build volume: 90mm x 90mm x 80mm (x,y,z)

Build atmosphere: Argon

Powder: Stainless Steel 316L, others possible

Slicing software:MaterialiseMagics

We have a long history of researching additive manufacturing, including the original directed energy deposition powder blown methods and large-scale wire fed systems. The Concept Laser was donated by GE and has enabled us to begin working more actively in the SLM space. It also provides an educational opportunity for a variety of students in our department and beyond.

Laser: 500W continuous wave IPG laser

Build volume: 100mm x 100mm x 100mm (x,y,z)

Axes: 6 axes

Build atmosphere: Argon

Powder: All (demonstrated on Ti)

High precision stages for independent motion and imaging/diffraction experiments.

We have a long history of researching additive manufacturing, including the original directed energy deposition powder blown methods and large-scale wire fed systems. This system will be used in upcoming research programs designed for beam line analysis and the development of new sensors.

Automated polishing systemoMulti–platen cassette system for polisheroAutomatic polishing solution dispenser for 6 solutions + water

Fully automated inverted microscope

Cleaning stationo2 ultrasonic cleaning stationso3 washing/etching/dip well stationso1 drying station

Slice Thickness: 0.2 –10 micronsSlice Rate: Up to 20 per hour

Sample Size: 1.25″ or 1.5″ mounted samples, additional flat plate holder for other geometries

Etching: Automatic

Optical Illumination: Bright Field

Microstructural Data Collection: Real time

The Robo-Met.3D is another system with which our group has extensive experience. We value its ability to make 3D materials characterization more accessible. In this system, which was funded under an ONR DURIP program and installed in 2018, we have worked to integrate SRAS into it as another characterization instrument.

TEM: FEI Tecnai G2–F20 at the Sensitive Instrument Facility.

Automatic precession alignment with TOPSPIN control software.

Automatic diffraction pattern indexing with ASTAR.

Reciprocal lattice reconstruction (3D) capabilities.

We began our work with precession electron diffraction before it was widely known, purchasing our first system in early 2011. When the group transitioned to Iowa State University, it was part of the first infrastructure we reestablished. We have used it to develop new ways of quantifying and spatially mapping dislocation densities, assess the character of large populations of grain boundaries, and are, to this day, imagining new ways to use it to extract critical information regarding the crystal structure, interfacial structures, and defect structures of materials, as well as assess symmetry.