Stress Relaxation Measurement With Nanoindentation

As per ASTM E 328, Standard Test Methods for Stress Relaxation for Materials and Structures, external force is initially applied on the material or structure to reach a constant constraint, and then the change in the external force necessary to maintain this constraint is measured as a function of time. The major difficulty in the stress relaxation test is maintaining the constant constraint. The nanoindentation module of Nanovea Mechanical Tester accurately measures the stress relaxation by applying the close loop control of the load with ultra-sensitive load cell and piezo. The piezo reacts real-time to keep the constraint constant while the change in load is measured and recorded by the high precision load cell. This measurement can be performed on virtually all types of materials without the stringent requirement of sample dimension. Multiple stress relaxation tests can be performed on the same flat sample to ensure the test repeatability, which substantially reduces the cost on sample manufacturing and machining.

Honeycomb Panel Finish, Tribology and Mechanical Properties

Honeycomb panel analysis including mechanical properties using microindentation, surface finish using 3D profilometery and wear resistance using Tribometer.




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MS&T, the annual materials science conference held by four technical societies, offers an unreplicated technical program addressing structure, properties, processing and performance across the materials community. The exposition showcases a wide variety of equipment and services to the automotive, aerospace, instrumentation, medical, oilfield and energy industries. Learn more about each society here.

Controlled Humidity Nanoindentation of Polymer Films

The mechanical properties of polymer is modified as the environmental humidity elevates. Transient moisture effects, a.k.a. mechano-sorptive effects arises as the polymer absorbs high moisture content and experiences accelerated creep behavior. The higher creep compliance is a result of complex combined effects such as increased molecular mobility, sorption-induced physical aging and sorption-induced stress gradients.

Therefore, a reliable and quantitative test (Humidity Nanoindentation)of the sorption-induced influence on the mechanical behavior of polymeric materials at different moisture level is in need. The Nano module of the Nanovea Mechanical Tester applies the load by a high-precision piezo and directly measures the evolution of force and displacement. Uniform humidity is created surrounding the indentation tip and the sample surface by an isolation enclosure, which ensures measurement accuracy and minimizes the influence of drift caused by humidity gradient.

Controlled Humidity Nanoindentation of Polymer Films

Humidity Effect On Paper Flatness

Paper flatness is critical to the proper performance of printing paper. It communicates functional characteristics and makes an impression of the paper quality. A better understanding of the effect of humidity on paper flatness, texture and consistency allows optimizing the processing and control measures to obtain the best product. Quantifiable, precise and reliable surface inspection of the paper in different humid environments is in need to simulate the use of paper in the realistic application. The Nanovea 3D Non-Contact Profilometers utilizes chromatic confocal technology with unique capability to precisely measure the paper surface. A humidity controller provides precise control of the humidity in a sealed chamber where the test sample is exposed to the moisture.

Humidity Effect On Paper Flatness

Humidity Tribology Effect On DLC Coating

The DLC coating exhibits very low COF against steel ball (below 0.1) under high vacuum and dry condition. However, it has also been reported that the DLC is very sensitive to the change of environmental conditions, particularly the relative humidity tribology(RH). The environment with a high humidity and oxygen concentration may lead to significant increase of the COF. In order to simulate the realistic environmental conditions of the DLC coating for tribological applications, reliable wear evaluation in a controlled and monitored humidity is in need. It allows users to properly compare the wear behaviors of the DLC coatings exposed to different humidity and to select the best candidate for the targeted application.

Humidity Tribology Effect On DLC Coating

Cutting Tool Edge Measurement in Seconds

Irvine CA, July 27, 2016 – Conventional profilometry scans sample surfaces from a single, fixed direction.  This is only appropriate for measuring sufficiently flat samples, as opposed to cylindrical shapes that require a precise 360° rotation. For an application such as characterizing the helical cutting edge of a tool, a conventional machine would need multiple scans from different angles of the entire part, as well as significant post scan data manipulation. This is often too time consuming for QC applications that only require measurements from very specific regions.

NANOVEA’S rotational stage solves this problem with simultaneous motion control of the lateral and rotational axes. This technique eliminates the time consuming need of measuring the entire part and continuous realignment. Instead, the full circumference of the entire cutting edge can be determined in seconds. All desired angles and features can be directly determined from the scan, with no need for the extensive stitching together of multiple files.

NANOVEA’s chromatic confocal technique offers far greater resolution, down to 2.7 nm, and accuracy than Focus Variation competitors. The raw surface height is measured directly from the detection of the wavelength focused on the surface, with none of the errors caused by Interferometry techniques, no field of view limitations, and no need for sample surface preparation. Materials with extremely high or low reflectivity can easily be measured and very high wall angles are accurately characterized without any issue.

Coupled with NANOVEA’s line sensor, a bar of data up to 4.78mm wide can be captured in a single pass, while moving linearly for up to 150mm in the scanning direction. Simultaneously, the rotational stage can revolve the sample at the desired speed. Put together, this system allows for the creation of a continuous 3D height map of the entire circumference of a cutting edge, with any pitch or radius, in a fraction of the time when compared to other technologies.

See App Note: Rotational Measurement Using 3D Profilometry

Polymer Morphology by Heat Deformation

Surface deformation of materials induced by environmental elements such as temperature, humidity and corrosion is vital to its service quality and functionality. Accurate 3D polymer morphology measurement allows quantifying the physical deformations of the surface form, roughness, volume/area, etc. Surfaces prone to deformation due to contact wear, high heat and others need regular inspection to ensure performance reliability.

Polymer Morphology by Heat Deformation Using 3D Profilometry

Teflon Mechanical Properties at High Temperature

At elevated temperatures, heat changes teflon mechanical properties such as the hardness and viscoelasticity, which may result in mechanical failures. A reliable measurement of the thermo-mechanical behavior of polymeric materials is in need to quantitatively evaluate the candidate materials for high temperature applications. The Nano module of the Nanovea Mechanical Tester studies the Hardness, Young’s Modulus and Creep by applying the load with a high-precision piezo and measuring the evolution of force and displacement. An advanced oven creates a uniform temperature surrounding the indentation tip and the sample surface throughout the nanoindentation test so as to minimize the effect of thermal drift.

Teflon Mechanical Properties at High Temperature Using Nanoindentation

High Temperature Arc Reciprocating Wear

ASTM G133 3 is a widely used standard setup for testing the reciprocating sliding wear behaviors of materials. Due to the back and forth movement of the sample involved during the arc reciprocating wear testing, it is challenging to design an oven that fully enclose the sample and reaches a high and homogenous temperature. Our previous study has shown that the material tested using reciprocating and rotational setups can exhibit significantly different wear behaviors. Therefore, in order to study the reciprocating wear behaviors of materials at elevated temperatures, we developed the arc wear test setup. It rotates the sample stage for pin-on-disc test and continuously oscillates it clockwise and counterclockwise, creating a arc reciprocating sliding motion for the sample. The contact of the wear process can be totally enclosed in a large oven which ensures uniform and stable temperature up to 950oC surrounding the sample and the counter material.

Arc Reciprocating Wear at High Temperature Using Tribometer

App Notes