Average Residual Stresses in Hard Physical Vapor Deposited (PVD) Coatings

2019 ◽  
Vol 799 ◽  
pp. 20-25
Author(s):  
Harri Lille ◽  
Alexander Ryabchikov ◽  
Jakub Kõo ◽  
Valdek Mikli ◽  
Eron Adoberg ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Front Surface ◽  
Back Surface ◽  
Length Variation ◽  
Pvd Coatings ◽  
Cross Sectional ◽  
Average Residual ◽  
Thin Walled ◽  
Compressive Residual Stresses ◽  
Very High

In this study we determined average residual stresses in hard nitride PVD AlCrN, TiAlN and TiCN coatings through simultaneous measurement of length variation in thin-walled tubular substrates and of the curvature of plate substrates. A device for measurement of the length of the tube was developed. Inside the depositing chamber the tube and the plate were fixed parallel in the relation to the axis of the rotating cathode. One batch of plate samples was produced by deposition on front surface (facing the cathode) and the other batch, by deposition on back surface (with back to the cathode). The cross-sectional microstructure and thickness of the coatings were investigated by means of scanning electron microscopy (SEM). The thicknesses of the coatings deposited on front and back surfaces of the plates and on the tube were significantly different. The values of average compressive residual stresses, determined by both methods, were very high irrespective of coating thickness. It was found that the values of compressive residual stresses in the coating were dependent on the shape of the substrate and on its position in the relation to the axis of the rotating cathode.

scholarly journals Residual Stresses on Various PVD Hard Coatings on Tube and Plate Substrates

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1054
Author(s):  
Harri Lille ◽  
Alexander Ryabchikov ◽  
Priidu Peetsalu ◽  
Liina Lind ◽  
Fjodor Sergejev ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Rear Surface ◽  
Front Surface ◽  
Length Change ◽  
Hard Coatings ◽  
Wear Testing ◽  
Tube Length ◽  
Length Variation ◽  
Cross Sectional ◽  
Compressive Residual Stresses

In this study, the average residual stresses were determined in hard PVD nACRo (nc-AlCrN/a-Si3N4), nACo (nc-AlTiN/a-Si3N4), AlCrN, TiAlN, and TiCN commercial coatings through the deflection of the plate substrates and the simultaneous measurement of length variation in thin-walled tubular substrates. The length measuring unit was used for the measurement of any length change in the tubular substrate. A change in tube length was reduced to the deflection of the middle cross-section of the elastic element for which deformation was measured using four strain gauges. The cross-sectional microstructure and thickness of the coatings were investigated by means of scanning electron microscopy (SEM), and a determination was made of the chemical composition of the coatings and substrate by means of energy dispersive X-ray spectroscopy (EDS). The values of average compressive residual stresses, as determined by both methods, were very high (with a variation of between 2.05 and 6.63 GPa), irrespective of coating thickness, but were dependent upon the shape of the substrate and on its position in relation to the axis of the rotating cathode. The thicknesses of the coatings that were deposited on the plates with two parallel fixings (such as the nACRo coatings on the front surface at 6.8 μm and on the rear surface at 2.9 μm) and on the tubular substrates (10.0 μm) were significantly different. The higher average compressive residual stresses in the coating correlate to the higher average relative wear resistance that was obtained during field wear testing.

Evaluation of Residual Stresses in PVD Coatings by Means of Strip Substrate Length Variation and Curvature Method of Plate Substrate

2017 ◽  
Vol 267 ◽  
pp. 212-218 ◽  
Author(s):  
Harri Lille ◽  
Alexander Ryabchikov ◽  
Jakub Kõo ◽  
Eron Adoberg ◽  
Liina Lind ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Length Change ◽  
Steel Plates ◽  
Length Variation ◽  
Pvd Coatings ◽  
Compressive Stresses ◽  
Steel Strips ◽  
Middle Cross Section ◽  
Method Strip

The aim of the study was to determine macroscopic residual stresses in Physical Vapor Deposits (PVD) coatings through measurement of the length variation of the strip substrates coated on both sides. The length change of the strip was reduced to the deflection of the middle cross-section of the elastic element and was recorded by four strain gauges. For validating the obtained results, the conventional curvature method was used. As an application, residual stresses in hard AlCrN PVD coatings were investigated. The coatings were nanolayered to achieve better coating toughness for blanking and punching applications. The steel strips and steel plates with two thicknesses were used as the substrate. The values of the compressive residual stresses, determined by both methods for the investigated coatings, were very high (3.3 -3.6 GPa) independent of coating thickness and practically equal within the measurement uncertainty of the method. Good agreement between the experimental results obtained with both methods suggests that the presented method, strip length variation, is applicable for determination of residual stresses in coatings. Compressive stresses in coatings are desirable as they strengthen the coating.

scholarly journals Microstructure and mechanical properties of Titanium grade 23 produced by selective laser melting

2021 ◽  
Vol 21 (4) ◽  
Author(s):  
Piotr Nikiel ◽  
Mirosław Wróbel ◽  
Stefan Szczepanik ◽  
Michał Stępień ◽  
Krzysztof Wierzbanowski ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Laser Scanning ◽  
Tensile Elongation ◽  
Product Characterization ◽  
Technological Practice ◽  
Testing Techniques ◽  
Titanium Grade ◽  
Compressive Residual Stresses ◽  
Very High ◽  
Low Porosity

AbstractSelective laser melted Titanium grade 23 was characterized by low porosity, relatively large surface roughness and pronounced surface texture (i.e. surface grooves orientation). The band/layer microstructure was built of mixed α and β phases. The as printed structure exhibited very high compressive residual stresses with strong anisotropy (i.e., − 512 ± 17 MPa and − 282 ± 14 MPa along the laser scanning direction and along the transverse direction, respectively) and strong fiber crystallographic texture. The latter one is responsible for the anisotropy of hardness in the material. Annealing at 600 °C during four hours significantly removed residual stresses (i.e. to − 14 ± 2.8 MPa) and slightly weakened the texture. Yield strength, 1120 ± 50 MPa, and ultimate tensile strength, 1210 ± 50 MPa, of the annealed material are significantly higher and tensile elongation, 3.9%, lower than for commercial Titanium grade 23. Final mechanical polishing to obtain flat and relatively smooth surface induced desired compression residual stress in the subsurface (i.e., equal to about − 90 MPa). Low absorbed gas contents (oxygen, nitrogen, hydrogen) and low porosity of the printed material indicates the correctness of the technology and allows the printed material to be classified as meeting the requirements of ASTM standards for Titanium grade 23. Besides traditional testing techniques, the optical profilometry, X-ray analysis (texture and residual stresses measurement) and infrared absorption method were applied for the product characterization and some potential of these testing methods and usefulness in technological practice was discussed, what can be particularly interesting both to practitioners from industry and researches from scientific laboratories.

The relationship betweenparityand the incident of perinealruptures on women’s physiological maternity

2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Evi Rosita ◽  
Siti Nurnaningrum
Keyword(s):  
Public Health ◽  
Health Center ◽  
P Value ◽  
Chi Square ◽  
Cross Sectional ◽  
Midwifery Care ◽  
Public Health Center ◽  
Record Data ◽  
The Relationship ◽  
Very High

There are about 2.8 million incident of perineal rupture in maternal physiological labor. In 2050,it is estimated that the incidence of perineal rupture can be 6.3 million if it is not accompanied by a good midwifery care. In 2016, in Trawas, there was (89%) perineal rupture in primiparas and (57%) perineal rupture in multiparas. Perineal rupture incidences due to parity were still very high. This study aims to analyze the relationship between parity and the incidence of perineal rupture . It is quantitative studyusing a cross sectional approach, by using analysis of physiological maternity women  medical record data from January to April 2017 of 130 peoplein Trawas Public Health Center, Mojokerto Regency.The dataanalysis used was Chi - Square , indicated by p value = 0,000 with ɑ = 0,05. It means that the value of p <ɑ, so H1 is accepted. It can be concluded that there is a relationship between parity and the incidence of perineal rupture on physiological maternity women in Trawas Public Health Center,Mojokerto Regency. Midwives can apply collaboration with patients and their families to have physical and psychologicalpreparation with an alternative of hypnobirthing methods.

HIGH PREVALENCE OF MALNUTRITON AND WORM INFECTION AMONG VAN KIEU AND PAKOH CHILDREN AGED 12-36 MONTHS IN DAKRONG DISTRICT, QUANG TRI PROVINCE

2012 ◽  
pp. 129-134
Author(s):  
Thi Lan Tran ◽  
Thi Huong Le ◽  
Xuan Ninh Nguyen
Keyword(s):  
Cross Sectional Study ◽  
Age Group ◽  
Infection Status ◽  
Sectional Study ◽  
Group Recommendation ◽  
Related Factors ◽  
Normal Children ◽  
Cross Sectional ◽  
High Prevalence ◽  
Very High

Objectives: Assess the nutritional status, worm infection status and some related factors among children aged 12-36 months of Dakrong district, Quang Tri province. Subject and method: A cross sectional study was carried out in 2010, in 680 children aged 12-36 months in 4 communes of Dakrong district, Quang Tri province. Results: The malnutrition rate was 55.0% for underweight, 66.5% for stunting and 16.2% for wasting. The prevalence of malnutrition increases by age group. The prevalence of worm infection was 31.6%, the highest prevalence was belong to Ascaris infection (24.6%), followed by Hookworm and Trichuris (6.5% and 6.2%, respectively). The prevalence of worm infection among children under two is very high (27.0%). The prevalence of worm infection was distributed quite equally between the malnutrition children group and normal children group. Recommendation: Early deworming forchildren from 12 months should be considered as important strategy against the malnutrition of children in Dakrong district, Quang Tri province

Cross-sectional Mapping of Residual Stresses Using the Contour Method

2019 ◽  
Vol 88 (6) ◽  
pp. 472-475
Author(s):  
Daisuke TAKAKURA ◽  
Hiroshi FUKAZAWA ◽  
Mitsuyoshi TSUNORI
Keyword(s):  
Residual Stresses ◽  
Contour Method ◽  
Cross Sectional

scholarly journals X-ray Determination of Compressive Residual Stresses in Spring Steel Generated by High-Speed Water Quenching

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1154
Author(s):  
Diego E. Lozano ◽  
George E. Totten ◽  
Yaneth Bedolla-Gil ◽  
Martha Guerrero-Mata ◽  
Marcel Carpio ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
High Speed ◽  
Spring Steel ◽  
X Ray Diffraction ◽  
Laboratory Equipment ◽  
X Ray ◽  
Water Chamber ◽  
Hardened Case ◽  
Compressive Residual Stresses

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.

Poor social support and loneliness in chronic headache: Prevalence and effect modifiers

Cephalalgia ◽  
2021 ◽  
pp. 033310242110203
Author(s):  
Maria Lurenda Westergaard ◽  
Cathrine Juel Lau ◽  
Karen Allesøe ◽  
Anne Helms Andreasen ◽  
Rigmor Højland Jensen
Keyword(s):  
Social Support ◽  
Odds Ratio ◽  
Chronic Headache ◽  
Medication Overuse ◽  
Odds Ratios ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Self Rated Health ◽  
Poor Social Support ◽  
Very High

Objective To explore the prevalence of poor social support and loneliness among people with chronic headache, and how these might be effect modifiers in the relationships between chronic headache and stress, medication overuse, and self-rated health. Background Poor social support and loneliness are consistently linked to worse health outcomes. There are few epidemiologic studies on their effect on headache. Methods The Danish Capital Region Health Survey, a cross-sectional survey, was conducted in 2017. Participants were asked about headache, pain medication use, social support, loneliness, perceived stress, and self-rated health. Data were accessed from sociodemographic registers. Logistic regression analyses were performed to test for effect modification. Results The response rate was 52.6% (55,185 respondents) and was representative of the target population. People with chronic headache were more likely to report poor social support and loneliness compared to those without chronic headache ( p < 0.0001 for both). Odds ratios for the combination of chronic headache and poor social support were very high for stress (odds ratio 8.1), medication overuse (odds ratio 21.9), and poor self-rated health (odds ratio 10.2) compared to those without chronic headache and with good social support. Those who reported both chronic headache and loneliness had a very high odds ratio for stress (odds ratio 14.4), medication overuse (odds ratio 20.1), and poor self-rated health (odds ratio 15.9) compared to those without chronic headache and low loneliness score. When adjusted for sociodemographic factors, poor social support and loneliness were not significant effect modifiers in almost all these associations. Loneliness was a significant effect modifier in the association between chronic headache and medication overuse, but exerted greater effect among those who did not report they were lonely. Conclusion Poor social support and loneliness were prevalent among people with chronic headache. The combination of chronic headache and poor social support or loneliness showed higher odds ratios for stress, medication overuse, and poor self-rated health compared to those with good social support and low loneliness scores. The effect of loneliness in the relationship between chronic headache and medication overuse warrants further study.

scholarly journals The Pelvic Incidence Stratified Sagittal Spinopelvic Alignment in Asymptomatic Chinese Population With Different Age Groups

2021 ◽  
pp. 219256822198964
Author(s):  
Siyu Zhou ◽  
Zhuoran Sun ◽  
Wei Li ◽  
Da Zou ◽  
Weishi Li
Keyword(s):  
Chinese Population ◽  
Pelvic Incidence ◽  
Sagittal Alignment ◽  
Age Groups ◽  
Vertical Axis ◽  
Elderly Subjects ◽  
Sagittal Vertical Axis ◽  
Cross Sectional ◽  
Sagittal Parameters ◽  
Very High

Study Design: Cross-sectional study. Objective: To provide the age- and pelvic incidence-related variations of sagittal alignment in asymptomatic Chinese population. Methods: This study recruited asymptomatic adult subjects. All subjects undertook the standing whole spinal radiograph and the sagittal parameters were measured: sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI) and pelvic tilt (PT). All subjects were divided into young, middle aged and elderly groups, then each age group was further divided into 5 subgroups (very low, low, average, high and very high) based on PI values. The relations between PI, age and other parameters were evaluated. The differences in sagittal parameters of each PI subgroup were compared. Results: 546 subjects were included with an average age of 38.6 years (18 to 81). The number of subjects over 70 years and with very low PI was relatively small. The average of PI, TPA, PT and LL were 45.9° ± 8.4°, 6.4° ± 6.2°, 11.9° ± 6.6° and 49.2° ± 10.1°, respectively. SVA, TPA, TK and PT increased with age ( P < 0.05), while SVA, TPA, PT, PI-LL also increased with PI ( P < 0.05). LL, PT, TPA, PI-LL and LL-TK were different among the 5 PI subgroups ( P < 0.05). However, the values of LL in elderly subjects with high and very high PI were similar. Conclusion: The age- and PI-related variations in sagittal alignment of Chinese population were provided. The sagittal parameters were significantly influenced by age and PI. The individual pelvic morphology should be carefully considered during the assessment and restoration of sagittal balance.

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