Design And Experiments Of Micro/Nano-indentation Platform At High Temperature

Mico/nano-indentation testing technology has become one of the mainstream means in the test of material microscopic mechanical properties. This high-resolution method is well known for its advantages in several aspects, as it could convenient to identify a wide variety of test parameters, including: hardness, elastic modulus, etc. Combining the regional deformation of the material structure and microstructure evolution measurements together, it could be easy to study the evolutionary mechanism of material’s properties under loads. Also, it’s quite easy to do the material sample preparation.However, the properties would change a lot for the material’s actual working environment is extremely complex under multi-physics effects, such as: temperature field, electromagnetic fields, etc. And the parameters of the material’s properties will vary according to changes in their environment, which would prove one thing: material parameters of micro/nano-indentation test under normal temperature can’t characterize the actual performance so it’s more important to study the micro/nano-indentation test under varying temperature. Micro/nano-indentation test under high-temperature environment is of great significance for the study of material’s mechanical properties under high temperature, also beneficial for the life prediction and reliability evaluation.This paper reviews the background and significance of high-temperature micro/nano-indentation testing technology and introduces the current domestic and international development. Related studies are summarized on two aspects: indentation response and device structure. Also, this paper studies on the basic theory of micro/nano-indentations test, expounds key technologies of normal and high temperature indentations test, analyzes the effects of high temperature on indentations test and designs the overall structure of the platform by modular way. To summarize, this article establishes the three-dimensional model of micro/nano-indentations test platform for high-temperature, performs dynamic and static mechanics and thermodynamics simulation for key parts and the whole machine using the FEA method. Based on the work above, the platform integration is completed and load / displacement sensors are calibrated, then this platform is tested within the range from room temperature to 1000 ℃ and the stability is accepted. Also, the two sensor detection scheme is verified to be feasible, which aims to broaden the loading scale range of testing device.Using standard hardness block 700-800HV50 for calibration, the hardness test error is 3.2% and modulus test error is 8.6% compared with commercial instruments, and the device is proved to be of good repeatability. Result shows that hardness and elastic modulus error rate is 1.7% and 8.5% respectively using the motor drive way. Finally, the response experiments of fused silica and superalloy GH1131 are conducted by the platform after calibration, from which we could easily get these conclusions: as the temperature increases, the hardness of the fused silica decreases and the elastic modulus increases, while GH1131’s hardness and modulus decrease.