scholarly journals INDENTATION SIZE EFFECT OF HEAT TREATED ALUMINUM ALLOY

2019 ◽  
Vol 25 (3) ◽  
pp. 166 ◽  
Author(s):  
Jozef Petrík ◽  
Peter Blaško ◽  
Andrea Vasilňaková ◽  
Peter Demeter ◽  
Peter Futáš

<p class="AMStitle">Abstract</p><p class="AMSmaintext">The aim of the submitted work is to study the influence of applied  loads ranging from 0.09807 N to 0.9807 N on measured values of micro-hardness of heat treated aluminum alloy 6082. The influence of applied load on a measured value of micro-hardness was evaluated by Meyer’s index n, PSR method and by Analysis of Variance (ANOVA).  The influence of the load on the measured value of micro-hardness is statistically significant and the relationship between the applied load and micro-hardness manifests the moderate reverse ISE. As the temperature of the solution treatment rises, the YS/UTS ratio and also Meyer’s index n, measured and “true hardness“  increase. On the other hand, its effect on the plastic properties of the alloy is ambiguous.</p>

2011 ◽  
Vol 18 (2) ◽  
pp. 223-234 ◽  
Author(s):  
Jozef Petrík ◽  
Pavol Palfy

The Influence of the Load on the HardnessThe 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 micro-hardness is statistically significant for majority of calibrations.


2016 ◽  
Vol 61 (4) ◽  
pp. 1819-1824 ◽  
Author(s):  
J. Petrík

AbstractThe 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.


2019 ◽  
Vol 116 (6) ◽  
pp. 622
Author(s):  
Jozef Petrík ◽  
Peter Blaško ◽  
Mária Mihaliková ◽  
Andrea Vasilňáková ◽  
Vojtech Mikloš

The aim of the submitted work is to study the relationship between the local deformation and the indentation size effect (ISE). A local value of reduction of the area (Z) was used as the measure of the deformation. Applied loads in the micro-hardness test ranged between 0.09807 to 0.9807 N. The micro-hardness was measured on the cross section in the longitudinal axis of the fractured sample after the uniaxial tension test. The material of the sample was 99.5% aluminium. The influence of both load and deformation on the ISE was evaluated by the analysis of variance (ANOVA). The influence of the load was also evaluated by Meyer’s index n, PSR method, and Hays–Kendall approach. The influence of both factors on the measured value of micro-hardness and therefore on the ISE is statistically significant. The ISE is normal in the areas with high deformation, on the contrary, in areas with low deformation, it has a “reverse” character. The difference between load independent “true hardness” and measured micro-hardness HV0.05 increases with increasing deformation.


Author(s):  
J. Petrík ◽  
P. Blaško ◽  
M. Mihaliková ◽  
V. Mikloš

The aim of the submitted work is to study the relationship between the local deformation and the Indentation Size Effect (ISE). A local value of reduction of the area (Z) was used as the measure of the deformation. Applied loads in the micro-hardness test ranged between 0.09807 N to 0.9807 N. The micro-hardness was measures on the cross section in the longitudinal axis of the fractured sample after the uniaxial tension test. The material of the sample was 99.5% aluminium. The influence of the load was also evaluated by Meyer's index n, PSR method and Hays therefore on the ISE statistically significant. The ISE is normal in the areas with high deformation, on the contrary, in areas with low deformation it has the "reverse" character. The difference between load independent "tru hardness" and measured micro-hardness HV0.05 increases with increasing deformation


2015 ◽  
Vol 819 ◽  
pp. 39-44 ◽  
Author(s):  
Shamsul Baharin Jamaludin ◽  
Mohd Hanif Abdullah ◽  
Mohd Noor Mazlee ◽  
Kamarudin Hussin

This work examines the effect of solution heat treatment temperature on the tensile strength of Al-Mg-Si aluminum alloy. All samples were machined according to the ASTM B557. The samples were solution treated at 450°C and 530°C and followed by ageing at 160°C for 0, 5, 10, 15 and 20 hours. Tensile test was carried out on the samples after heat treatment. The results showed that the highest tensile strengths (201.69 MPa) was given by the sample solution heat treated at 530 °C for 5 hours followed by 20 hours aging at 160 °C. Whereas, the lowest tensile strength (98.52MPa) was given by the sample solution treated at 450°C for 20 hours. Tensile strength was increased with ageing process and decreased for over-aged samples.


2011 ◽  
Vol 471-472 ◽  
pp. 1171-1176 ◽  
Author(s):  
A. Bahrami ◽  
A. Razaghian ◽  
M. Emamy ◽  
H.R. Jafari Nodooshan ◽  
G.S. Mousavi

In this study, the relationship between microstructures and mechanical properties of the extrusion processed Al-15wt.%Mg2Si composite was investigated after applying various extrusion ratios (6:1, 12:1 and 18:1) and solution treatment. Various techniques including metallography, tensile testing and SEM fractography were utilized to characterize the mechanical behavior of the MMC. Results demonstrated that extruded and heat treated composite possesses considerably higher strength and enhanced ductility in comparison with the as-cast samples. It was also found that heat treatment and extrusion processes do not change the primary Mg2Si morphology considerably, but its size increases as extrusion ratio decreased. Heat treatment and extrusion ratio effects on tensile strength, elongation of extruded specimens were also studied in this work.


2014 ◽  
Vol 217-218 ◽  
pp. 274-280
Author(s):  
Kang Du ◽  
Da Quan Li ◽  
Xiao Kang Liang ◽  
Qiang Zhu

Turbocharger impellers undergo extreme cyclic speed conditions and thus fatigue fracture in service. Any kind of defects, even defects with sizes of tens of micrometres, can make significant impact on service life of the impellers. The alloy used for thixocast impellers is the aluminum alloy 319s. T61 heat treatment is used to improve mechanical properties. However, the solution treatment in the standard T61 heat treatment of the 319s alloy can induce incipient melting defects. This paper carried out systematic study of formation of defects caused by the incipient melting during solution treatment in the thixocast and heat treated impellers, using optical and scanning electron microscope. Based on the study, the critical temperature of incipient melting is detected. An optimized two-stage solution treatment is therefore proposed.


Author(s):  
A.H. Advani ◽  
L.E. Murr ◽  
D.J. Matlock ◽  
W.W. Fisher ◽  
P.M. Tarin ◽  
...  

Plastic deformation is a key variable producing accelerated intergranular (IG) carbide precipitation and chromium-depletion (sensitization) development in stainless steels. Deformation above 20% also produces transgranular (TG) carbides and depletion in the material. Research on TG carbides in SS is, however, limited and has indicated that the precipitation is site-specific preferring twin-fault intersections in 316 SS versus deformation-induced martensite and martensite lath-boundaries in 304 SS. Evidences indicating the relation between martensite and carbides were, however, sketchy.The objective of this work was to fundamentally understand the relationship between TG carbides and strain-induced martensite in 304 SS. Since strain-induced martensite forms at twin-fault intersections in 304 SS and the crystallography of the transformation is well understood, we believed that it could be key in understanding mechanisms of carbides and sensitization in SS. A 0.051% C, 304 SS deformed to ∽33% engineering strain (40% true strain) and heat treated at 670°C/ 0.1-10h was used for the research. The study was carried out on a Hitachi H-8000 STEM at 200 kV.


2016 ◽  
Vol 109 (21) ◽  
pp. 211902 ◽  
Author(s):  
E. I. Ageev ◽  
V. Yu. Bychenkov ◽  
A. A. Ionin ◽  
S. I. Kudryashov ◽  
A. A. Petrov ◽  
...  

2010 ◽  
Vol 89-91 ◽  
pp. 377-382 ◽  
Author(s):  
S. Mineta ◽  
Shigenobu Namba ◽  
Takashi Yoneda ◽  
Kyosuke Ueda ◽  
Takayuki Narushima

Microstructural changes occurring in biomedical Co-Cr-Mo alloys with three carbon levels due to solution treatment and aging were investigated. Ingots of Co-Cr-Mo alloys with three different carbon levels were prepared by vacuum furnace melting; their chemical composition was Co-28Cr-6Mo-xC (x = 0.12, 0.25 and 0.35 mass%). Precipitates were electrolytically extracted from as-cast and heat-treated alloys. An M23C6 type carbide and a phase were detected as precipitates in as-cast Co-28Cr-6Mo-0.12C alloy, and an M23C6 type carbide and an  phase (M6C-M12C type carbide) were detected in as-cast Co-28Cr-6Mo-0.25C and Co-28Cr-6Mo-0.35C alloys. Only the M23C6 type carbide was detected during solution treatment. Complete precipitate dissolution occurred in all the three alloys after solution treatment. The holding time required for complete precipitate dissolution increased with increasing carbon content and decreasing solution treatment temperature. Complete precipitate dissolution occurred in the Co-Cr-Mo-C alloys solution treated at 1523 K for 43.2 ks; they were then subjected to aging from 873 to 1473 K for a heating time up to 44.1 ks after complete precipitate dissolution in solution treatment at 1523 K for 43.2 ks. The M23C6 type carbide with a grain size of 0.1–3 m was observed after aging. A time-temperature-precipitation diagram of the M23C6 type carbide formed in the Co-28Cr-6Mo-0.25C alloy was plotted.


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