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On the Load Dependence of Micro-Hardness Measurements: Analysis of Data by Different Models and Evaluation of Measurement Errors

Petrik J.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

1819--1824

EN

The influence of applied loads between 0.09807 N and 0.9807 N on measured values of micro-hardness was evaluated by Meyer’s index n, proportional specimen resistance model (PSR) and Hays – Kendall methods, Total Dispersion Zone and Analysis of Variance (ANOVA). The measurement was repeated 6 times using the same hardness reference block with standard hardness Hc = 327 HV0.05 as a sample. The influence of the load on the measured value of micro-hardness is statistically significant, and the relationship between applied load and micro-hardness manifests reverse indentation size effect (ISE) for most of “measurements”. The high value of the uncertainty of results can affect the existence and nature of ISE, especially at low loads.

2

The influence of the load on the hardness

Petrik J., Palfy P.

Metrology and Measurement Systems

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2011

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Vol. 18, nr 2

223-234

EN

The objective of the submitted paper is to analyze the influence of the load on the calibration of micro-hardness and hardness testers. The results were validated by Measurement Systems Analysis (MSA), Analysis of Variance (ANOVA) and Z-score. The relationship between the load and micro-hardness in calibration of micro-hardness testers cannot be explained by Kick's Law (Meyer's index "n" is different from 2). The conditions of Kick's Law are satisfied at macro-hardness calibration, the values of "n" are close to 2, regardless of the applied load. The apparent micro-hardness increases with the increase of the load up to 30 g; the reverse indentation size effect (ISE) behavior is typical for this interval of the loads. The influence of the load on the measured microhardness is statistically significant for majority of calibrations.

3

The dependence of properties of Al-Si alloy on copper content and cooling rate

Szarvasy P., Petrik J.

Archiwum Technologii Maszyn i Automatyzacji

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2001

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Vol. 21, Nr 1

151-160

EN

The aim of submitted work is the study of influences of Cu (1, 2 and 3%) and Sr concentrations and cooling rate (2 and 18°C o s(-1) on the castability, structural and mechanical parameters of the AlSilO castings. The Sr content 0.015% is sufficient for full modification of P phase and good mechanical properties at booth cooling rates. Cu has more significant effect on the mechanical properties than Sr content or cooling rate.

PL

Celem pracy jest zbadanie-wpływu zawartości miedzi (1, 2 i 3%) i strontu oraz szybkości chło-dzenia (2 i 18 K * (-1) na właściwości odlewnicze i strukturę stopu AlSilO oraz mechaniczne parametry wykonywanych z niego odlewów. Zawartość strontu wynosząca 0,015% jest dostateczna dla zapewnienia pełnej modyfikacji fazy Beta i dobrych właściwości mechanicznych. Miedź ma bardziej znaczący wpływ na właściwości mechaniczne niż zawartość strontu lub szybkość chłodzenia.