High temperature heating system

#This document pertains generally, but not by way of limitation, to mechanical testing and heating of samples at scales of microns and smaller.

#Indentation, scratch, tensile and compression testing at scales of microns or less are methods for quantitatively measuring mechanical properties, such as elastic modulus and hardness, of materials. For instance, probes capable of determining loading forces and displacement are used. In some examples, forces applied in mechanical testing at scales of microns or less are less than 10 N, with a typical displacement range being smaller than 500 μm, and with a noise level typically being better than 10 nm root mean squared (rms). Force and displacement data measured with the probe are used to determine the mechanical properties of the sample and one or more of the elastic or plastic characteristics and the associated material phase changes. In one example, for sample property estimation a micro/nano-indenter is integrated with a characterized indenter tip having a known geometry and known mechanical properties.

#Some of the emerging mechanical characterization techniques at scales of microns or less include, but are not limited to, quantitative transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in-situ mechanical testing (as well as optical microscope techniques in some instances). These in-situ mechanical testing techniques enable monitoring of the deformation of a sample in real time while measuring the quantitative mechanical data. Coupling a mechanical testing system configured for testing at scales of microns or less with electron or optical microscopy imaging allows researchers to study structure property correlation and the influence of pre-existing defects on the mechanical response of materials. In addition to imaging, selected-area diffraction can be used to determine sample orientation and loading direction influence on mechanical response. Moreover, with in-situ electron or optical microscopy mechanical testing, the deformation can be viewed in real-time rather than “post-mortem”. Performing in-situ mechanical testing at scales of microns or less can provide unambiguous differentiation between the many possible causes of force or displacement transients which may include dislocation bursts, phase transformations, shear banding or fracture onset. Mechanical testing at micron or nano scales with elevated temperature is an important part of material characterization for materials having phase changes or variant mechanical properties as temperature increases. Many materials and devices are designed to perform at temperatures other than room temperature. The thermo-mechanical reliability of advanced materials needs to be fully understood through proper material testing. Due to this reason, it is often preferred to test the mechanical properties of these materials at their operating temperatures. The measured data at the elevated temperature can be used to estimate the performance of the materials in their normal operating environment. For example, understanding the thermo-mechanical response of polymer composites designed for enhanced mechanical properties will result in lighter and stronger materials for aerospace and automobile industries, improving efficiency in the transportation sector and energy savings. Understanding the fundamentals of strengthening mechanisms in ceramic matrix composite materials will help to improve the lifetime usage of these materials in real world applications. To improve the efficiency of turbine powered jet engines, new turbines must run hotter with less cooling. Understanding the mechanical properties at elevated temperature of individual components such as disks, blades and nozzles is critical for the aerospace industry.

#In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

#FIG. 1 is a perspective view of one example of a high temperature sample testing system.

#FIG. 2 is a detailed perspective view of one example of a sample gripping and heating assembly.

#According to embodiments described herein, a system and method are provided for mechanically testing samples at the nano and micro scales (i.e., scales of microns or less), including, but not limited to, nanostructures, thin films and the like. Such testing is performed, in one example, to determine the mechanical properties of the materials composing the subjects. According to one embodiment, as will be described in greater detail herein, the testing assembly described herein includes a heating system including a sample gripping and heating assembly having heating and sensing elements positioned adjacent to a sample. The sample gripping and heating assembly grasps a sample substrate (e.g., a relatively large volume of material compared to a sample head and sample shaft). The sample gripping and heating assembly provides a compressive force to the sample substrate and fixes the substrate in place. A portion of the sample optionally extends from the sample substrate and is available for tensile mechanical testing without an intervening adhesive bond. The gripping surfaces grasp the large volume of the sample substrate and have minimal or no effect on the mechanical properties of the sample portion under examination (e.g., no deformation through the gripping engagement) while leaving the sample portion free for mechanical testing without an adhesive interface.

#The sample gripping and heating assembly provides opposed heating elements to simultaneously heat the sample at locations immediately adjacent to the sample. For instance, heating elements are disposed in the gripping surfaces and are configured to heat the sample at the gripping surface interface. Heat transfer is realized at the interface without conducting the heat transfer from more remote locations in the sample gripping and heating assembly. Further, heat transfer to remote portions of the sample gripping and heating assembly is substantially throttled through a combination of the shape of the sample gripping and heating assembly and the material selection for the heating grips and grip bases.

#FIG. 1 shows one example of a high-temperature sample testing system 100. As shown the high-temperature sample testing system 100 includes a sample gripping and heating assembly 102 including, for instance, two or more heating grips 104 (e.g., jaws) positioned on either side of an assembly housing 112 of the sample gripping and heating assembly 102. As further shown, the sample gripping and heating assembly 102 in one example includes a grip base 106 for each of the heated grips in 104. For instance, the heating grips 104 extend from or are a part of the grip bases 106. In another example, the sample gripping and heating assembly 102 includes a grip actuator 108 extending between clamp arms 113 (e.g., grip arms) at an assembly housing 112. The grip actuator 108 is sized and shaped to provide clamping force to each of the clamp arms 113 through operation of the grip actuator 108 to gradually move the heating grips 104 inwardly toward one another to grip and thereby clamp a sample positioned between the heating grips 104.