Wear Traces Research Articles

The Influence of a Lubricant Medium on the Development of Fretting Wear in an Interference Fit Connection

Fretting wear is a phenomenon occurring in many engineering objects, including push fit connections. In view of a large number of factors conducive to wear development, it is difficult to describe the mechanism of wear initiation and development. Therefore, various methods are sought to limit wear development. The use of a lubricant may be one of those ways. The aim of this article is to present the results of testing the influence of a lubricant medium on the development of fretting wear in interference fit connections. As a lubricant medium, MoS2 and Whitmore greases were used. For that purpose, wear tests were first conducted on the shaft/sleeve tribological kinematic pair, and then observations and laboratory measurements were performed. The observations demonstrated the presence of fretting wear traces on all tested samples, irrespective of the tribological kinematic pair being tested. The main kind of damage consisted of material build-ups which, during operation, become oxidised and, while moving along the connection, caused local abrasion and micropits. The best results in restricting the development of fretting wear were achieved with Whitmore grease.

Multi-stage experiments in Bronze Age spear combat: insights on wear formation, trauma, and combat contexts

This paper presents and discusses an experimental investigation of Bronze Age spear combat, with a focus on the impacts of bronze points against each other and other materials such as wooden shafts and shields, and animal tissues which act as a proxy for the human body.A replicable methodology comprising of a series of interconnected experiments gradually shifting the ratio between control and actualism is presented. The results offer fresh insights into prehistoric combat dynamics and the relationship between combat style, contact material, and the formation of wear traces. A comprehensive account of the morphology and formation dynamics of the damage inflicted on weapons, skin, and bone is provided, supported by detailed photographic documentation.The experimental design permitted to assess the frequency and type of collisions that would occur in actual spear combat. Furthermore, the development and modification of wear traces over time was also observed for the first time on spear points. The tests provided further insights into the level of training and skill required to execute specific movements with different combat objectives. Potential indicators for spear use in various combat contexts, such as fighting against multiple opponents versus more controlled encounters like duels, have been identified. The wear traces produced experimentally find convincing comparisons in the archaeological record.In conclusion, the results contribute to a more detailed understanding of Bronze Age armed encounters and provide robust guidance for interpreting combat marks on archaeological copper alloy weapons and on bones.

Exploring wear resistance: Three-body abrasion evaluation of HVOF-sprayed TiC and CoNi coatings on SS316 steel

This study investigated the performance of High-Velocity Oxygen Fuel (HVOF)-sprayed Titanium Carbide (TiC) and TiC + 50C (50%TiC + 50%CoNi) coatings on SS316 steel under three-body abrasion conditions. The microstructural analysis revealed a homogeneous distribution of TiC particles within the TiC coatings, while the TiC + 50C coatings exhibited a more complex microstructure due to the presence of Co-Ni alloy. Mechanical testing demonstrated the superior microhardness of TiC coatings compared to the SS316 substrate, suggesting enhanced wear resistance. Slurry abrasion tests indicated reduced mass loss rates for both TiC and TiC + 50C coatings compared to uncoated SS316 steel, with TiC coatings exhibiting superior resistance to abrasive wear. Post-abrasion examination revealed distinct wear patterns, including abrasive chipping, plowing marks, crater formation, wear traces, and surface ruggedness.

A Comparative Analysis of Enamel Surface Roughness Following Various Interproximal Reduction Techniques: An Examination Using Scanning Electron Microscopy and Atomic Force Microscopy.

Interproximal enamel reduction (IER) is a minimally invasive therapeutic procedure commonly used in orthodontics to address both functional and aesthetic issues. Its mechanical effects on enamel surfaces induce the formation of grooves, furrows, scratches, depressions, and valleys. The aim of this study was to assess the enamel surface roughness resulting after the application of currently available methods for interproximal reduction. Ninety freshly extracted human teeth were divided into six groups and subjected to the stripping procedure, using a different method for each group (diamond burs, abrasive strips of 90 μm, 60 μm, 40 μm, 15 μm, and abrasive discs). A single individual performed stripping according to the manufacturer's recommendations, involving interproximal reduction on one tooth's proximal face and leaving the other side untreated. Qualitative and quantitative assessment of the enamel surfaces was carried out using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), obtaining 2D and volumetric 3D images of the enamel surface microstructure and nanostructure. The study found that diamond burs and abrasive strips of 60 μm and 90 μm increased enamel roughness due to intense de-structuring effects, while the 40 μm polisher had a gentler effect and 15 μm abrasive strips and polishing discs preserved enamel surface quality and removed natural wear traces.

Effects of Tungsten Addition on the Microstructure and Properties of FeCoCrNiAl High-Entropy Alloy Coatings Fabricated via Laser Cladding.

This study examines the effects of different addition levels of tungsten (W) content on the microstructure, corrosion resistance, wear resistance, microhardness, and phase composition of coatings made from FeCoCrNiAl high-entropy alloy (HEA) using the laser cladding technique. Using a preset powder method, FeCoCrNiAlWx (where x represents the molar fraction of W, x = 0.0, 0.2, 0.4, 0.6, 0.8) HEA coatings were cladded onto the surface of 45 steel. The different cladding materials were tested for dry friction by using a reciprocating friction and wear testing machine. Subsequently, the detailed analysis of the microstructure, phase composition, corrosion resistance, wear traces, and hardness characteristics were carried out using a scanning electron microscope (SEM), X-ray diffractometer (XRD), electrochemical workstation, and microhardness tester. The results reveal that as the W content increases, the macro-morphology of the FeCoCrNiAlWx HEA cladding coating deteriorates; the microstructure of the FeCoCrNiAlWx HEA cladding coating, composed of μ phase and face-centered cubic solid solution, undergoes an evolution process from dendritic crystals to cellular crystals. Notably, with the increase in W content, the average microhardness of the cladding coating shows a significant upward trend, with FeCoCrNiAlW0.8 reaching an average hardness of 756.83 HV0.2, which is 2.97 times higher than the 45 steel substrate. At the same time, the friction coefficient of the cladding coating gradually decreases, indicating enhanced wear resistance. Specifically, the friction coefficients of FeCoCrNiAlW0.6 and FeCoCrNiAlW0.8 are similar, approximately 0.527. The friction and wear mechanisms are mainly adhesive and abrasive wear. In a 3.5 wt.% NaCl solution, the increase in W content results in a positive shift in the corrosion potential of the cladding coating. The FeCoCrNiAlW0.8 exhibits a corrosion potential approximately 403 mV higher than that of FeCoCrNiAl. The corrosion current density significantly decreases from 5.43 × 10-6 A/cm2 to 5.26 × 10-9 A/cm2, which suggests a significant enhancement in the corrosion resistance of the cladding coating.

Tool skill impacts the archaeological evidence across technological primates

The archaeological record offers insights into our evolutionary past by revealing ancient behaviour through stone and fossil remains. Percussive foraging is suggested to be particularly relevant for the emergence of tool-use in our lineage, yet early hominin percussive behaviours remain largely understudied compared to flaked technology. Stone tool-use of extant primates allows the simultaneous investigation of their artefacts and the associated behaviours. This is important for understanding the development of tool surface modification, and crucial for interpreting damage patterns in the archaeological record. Here, we compare the behaviour and the resulting material record across stone tool-using primates. We investigate the relationship of nut-cracking technique and stone tool modification across chimpanzees, capuchins, and long-tailed macaques by conducting standardized field experiments with comparable raw materials. We show that different techniques likely emerged in response to diverse nut hardness, leading to variation in foraging success across species. Our experiments further demonstrate a correlation between techniques and the intensity of visible percussive damage on the tools. Tools used with more precision and efficiency as demonstrated by macaques, show fewer use wear traces. This suggests that some percussive techniques may be less readily identified in the archaeological record.

Stone axes throw new light on Baltic stone age mortuary rites

Despite their ubiquity, Mesolithic lithic tools given as funerary offerings have rarely been studied in detail. Whereas personal ornaments (e.g. beads, pendants) are commonly interpreted as markers of social identity and status, archaeologists have struggled to understand the stone tools, commonly regarded as “utilitarian” items. As a result, this class of grave goods has not received the same level of attention, leaving a significant gap in our understanding of Mesolithic mortuary behaviours. Our research challenges long-lasting perceptions of lithic tools as strictly utilitarian objects and draws on studies of one of the most substantial stone axe funerary collections from one of the largest Stone Age cemeteries in Europe–Zvejnieki, Latvia. Evidence suggests the selection of unused axes as grave offerings, while unusual wear traces on an axe found in a female grave (no 57) raises questions about its use in the burial rites. Using a multi-proxy approach, we compare life histories of axes placed in burials to those recovered from contemporary, nearby settlement contexts. Finally, a strong correlation between axes and women and children at Zvejnieki challenges gendered stereotypes of stone tools, historically regarded as possessions of the adult male members of Stone Age societies.

Enhance the tribological performance of soft AISI 1045 steel through a CrN/W-DLC/DLC multilayer coating

Special equipment vehicles typically operate in complex environments, leading to wear and failure of the chassis's rotary seal shaft predominantly made of soft AISI 1045 steel. An effective approach to prolong the service life is to apply a hard coating on the working surface. Previous research have primarily concentrated on the coating for hard high-speed steel. However, the significant disparity in physical characteristics between soft AISI 1045 steel and the hard coating results in a weak interface adhesion. This study produces a CrN/W-DLC/DLC multilayer coating on the soft AISI 1045 steel with strong interfacial adhesion and superior friction and wear property through modulation of the CrN transition layer thickness. The multilayer coating consists of five layers, a CrN transition layer, a Cr layer, a Cr/WC alternating layer, a W-DLC/DLC alternating layer, and the topmost DLC layer. The thickest CrN interlayer coating achieves the Lc2 and Lc3 value of 13.9 ± 0.2 N and 20.4 ± 0.9 N. The optimized CrN/W-DLC/DLC coating reduces the internal stress of the DLC coating and enhances its adhesion. Importantly, the average friction coefficient and wear cross-sectional area of the CrN/W-DLC/DLC multilayer coatings decrease accordingly. The thickest CrN interlayer coating exhibits superior outstanding wear resistance evidenced by an average friction coefficient of 0.119, a steady-state friction coefficient of 0.097 and a wear volume of 1.508 × 106 μm3. The presence of a high proportion of sp2 bonds in the thickest CrN interlayer coating, which are susceptible to graphitization, along with a thicker transition layer that enhances the coating's support, leads to narrower wear traces. The primary wear mechanisms observed in the friction and wear test of CrN/W-DLC/DLC coatings are oxidative wear and tribo-abrasive wear. The work provides a significant promise for application in vehicle rotary seal components and a theoretical reference for enhancing the wear resistance of the seal surface.

Tribology performance of diamond-like carbon films on polyether-ether-ketone surfaces

Diamond-like carbon films were deposited on the polymer PEEK surface using a magnetron sputtering system. Experiments were conducted under varying rotational friction speed conditions. Special attention was devoted to assessing the surface condition of spherical spots post-friction experiments. Optical microscopy, friction tester, Raman spectroscopy, XPS analysis, and atomic force microscopy were employed to examine film surface morphology, atomic bonding structure, and surface roughness. The results indicate that thin film wear trace exhibits a graphitization trend that increases and then decreases, peaking around 350 rpm (0.11 m/s). Conversely, for spherical spots, the graphitization pattern is the opposite, suggesting a higher degree of disorder in the transferred film on these spots. XPS analysis reveals multiple chemical bonding structures between carbon and oxygen elements on the spherical spots. Notably, under the optical microscope, spherical spots exhibit clear directional alignment, which is absent on the film surface. This study introduces an innovative approach for producing diamond-like carbon films with lubricating and anti-wear properties. It also provides guidance for designing high-performance polymer tribo-systems in industrial applications.

Microbotanical analysis in artifacts of the CABUZA phase (900–1200 ce), Azapa Valley, northern Chile: Vessels and rites of “eating and drinking with the dead” in post‐Tiwanaku times

AbstractWe report observations of wear traces and microbotanical analysis of 29 ceramics, one pot of Cucurbita sp., and one wooden spoon—all artifacts of the AZ‐6 and AZ‐71 cemeteries of the Cabuza cultural phase (900–1200 ce), Azapa Valley, northern Chile—. The results show some unused artifacts (11) besides 21 samples that were positive for starches of Zea mays, Cucurbita sp., Manihot esculenta, Ipomoea batatas, or Phaseolus sp., in addition to vegetable remains (13 cases). This evidence is interpreted as an expression of funerary rites in post‐state times, which could be an inheritance of the Andean Tiwanaku State (ca. 500–1000 ce).

Preparation and tribological properties of porous polyimide modified by graphene

PurposeThe purpose of this article is to prepare graphene/polyimide composite materials for use as bearing cage materials, improving the friction and wear performance of bearing cages.Design/methodology/approachThe oil absorption and discharge tests were conducted to evaluate the oil content properties of the materials, while the mechanical properties were analyzed through cross-sectional morphology examination. Investigation into the tribological behavior and wear mechanisms encompassed characterization and analysis of wear trace morphology in PPI-based materials. Consequently, the influence of varied graphene nanoplatelets (GN) concentrations on the oil content, mechanical and tribological properties of PPI-based materials was elucidated.FindingsThe composites exhibit excellent oil-containing properties due to the increased porosity of PPI-GN composites. The robust formation of covalent bonds between GN and PPI amplifies the adhesive potency of the PPI-GN composites, thereby inducing a substantial enhancement in impact strength. Notably, the PPI-GN composites showed enhanced lubrication properties compared to PPI, which was particularly evident at a GN content of 0.5 Wt.%, as evidenced by the minimization of the average coefficient of friction and the width of the abrasion marks.Practical implicationsThis paper includes implications for elucidating the wear mechanism of the polyimide composites under frictional wear conditions and then to guide the optimization of oil content and tribological properties of polyimide bearing cage materials.Originality/valueIn this paper, homogeneously dispersed PPI-GN composites were effectively synthesized by introducing GN into a polyimide matrix through in situ polymerization, and the lubrication mechanism of the PPI composites was compared with that of the PPI-GN composites to illustrate the composites’ superiority.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2023-0415

A Unique Object from the 10th-Century Transylvanian Basin: The Mount Ornamented Sabretache of Grave No. 25 in Cluj-Napoca-Plugarilor Street

To the southeast of the Roman town of Napoca, 26 graves from the 10th century were discovered during the excavation of a Roman-period cemetery between 1985 and 1986. In the southern, slanted part of the funerary site, the individual of grave 25, the richest and most varied depositions and the only horse burial in the cemetery, was excavated. The most important object of the tomb’s very varied grave goods material is clearly the leather sabretache, which was ornamented with different types and sizes of mounts by the masters/leather craftsmen of the 10th century. Based on the available data, the sabretache, decorated with mounts, was not placed horizontally in the grave, but obliquely, at an angle of 45 degrees on the leg of the deceased person. Based on the structural and typological analysis of the mounts, the Cluj-Napoca mount ornamented sabretache shows a connection with the sabretaches of the Upper Tisza region and southern Poland and we can state that we do not know an identical analogy of the mounts on the sabretache from Cluj, so up to the present day, it is a unique piece. The traces of wear and repairs on the mounts of the Cluj-Napoca sabretache clearly indicate its long-term use. The signs of wear on the central mount of the sabretache and the biological age of the skeleton (60–65 years) indicate not only the lengthy use of the sabretache, but taking into account the above observations, they also confirm their placement in the grave in the second half of the 10th century. Based on the 14C samples’ results taken from the 60–65-year-old man and the horse sacrificed (4–5 years old), as well as the typochronological analysis of the finds, and the radiocarbon samples taken from the other six graves in the cemetery, grave 25 was most likely dug in the second half of the 10th century, approximately in the years 960–990. This also means that the life course of the senilis man, based on the available scientific researches, had begun around the years 910–930 and, which is at least as important, he was probably born in the vicinity of Cluj-Napoca.

A Comprehensive Study on Microstructure and Wear Behavior of Nano-WC Reinforced Ni60 Laser Coating on 17-4PH Stainless Steel

The surface of 17-4PH martensitic stainless steel was laser-cladded with Ni60 and Ni60+nano-WC composites and a comprehensive investigation was conducted of the microstructure and wear mechanism. The findings demonstrate that despite the added nano-WC particles being fused and dissolved during laser cladding, they still lead to a reduction in grain size and a decrease in crystallographic orientation strength. Furthermore, the dissolution of nano-WC makes the lamellar M23C6 carbides transform into a rod or block morphology, and leads to the CrB borides becoming finer and more evenly dispersed. This microstructural evolution resulted in a uniform increase in hardness and wear resistance, effectively preventing crack formation. When the nano-WC addition increased to 20 wt.%, there was a 27.12% increase in microhardness and an 85.19% decrease in volume wear rate compared to that of the pure Ni60 coating. Through analysis of the microstructure and topography of wear traces, it can be inferred that as the nano-WC addition increased from 0 wt.% up to 20 wt.%, there was a gradual transition from two-body abrasive wear to three-body abrasive wear, ultimately resulting in adherent wear.

Identifying the stone toolkit of Copper Age and Bronze Age metallurgists: A new contribution from use-wear and XRF analysis carried out on experimental tests

Use-wear analysis of stone tools involved in metallurgical processes is a recent field of research within functional analysis. In order to consolidate the methodological framework of such research, experiments were carried out on the production of copper and bronze objects. Several production steps were tested, on the basis of archaeological questions relating to sites dated from the 3rd and the 2nd millennium BC in north-west Europe. The crushing of copper ore was tested in order to compare use-wear traces created by three different actions: breaking block, fragmenting into small pieces and grinding into powder. In addition, various parts of a test group of copper and tin bronze axeheads and daggers were shaped by hammering: this hammering involved deburring and regularization of the sides of the axeheads and daggers, as well as thinning out the cutting edges immediately after casting or at a later stage. Finally, the sides and edges of the copper and bronze axeheads were abraded and polished. The combination of use-wear and XRF analysis of the tools involved in this series of experiments consolidates the methodological background of the functional analysis of stone tools. They allow better differentiation of wear traces resulting from the processing of ores within the broader spectrum of hard mineral materials. They also raise questions about the preservation of metal residues on the surface of stone tools depending on the different activities carried out. Finally, the distinction between copper and bronze objects is also discussed. Examples of the analysis of various metallurgists’ stone tools from the Early Bronze in north-west Europe support the demonstration.

Revealing the anti-friction mechanism of in-situ synthesized MoS2-S nanocomposite coating under different shear stress

This paper explores the anti-friction mechanisms of MoS2 in MoS2-S nanocomposite coating through molecular dynamics (MD) simulations. Our findings indicate that pin-on-disc wear has a lower and more stable coefficient of friction than reciprocating wear. The in situ synthesized MoS2 achieves friction reduction by promoting interlayer sliding by changing the plane spacing in response to tangential forces. In particular, for pin-on-disc wear, the rotational stresses results in isotropy friction and produces uniform strain and dislocation accumulation in the wear trace, leading to a stable and low COF. This study provides information on the sliding mechanism of MoS2 in self-lubricating coatings, which is essential to facilitate the development of new coatings for light alloys.

Zn-Based Alloys for Plain Bearings-Influence of Al and Cu Content on Mechanical Properties.

In recent decades, the requirements for plain bearing materials have continually increased, especially with new applications such as wind turbines, which require larger bearings. These new applications have completely different property profiles compared with, for example, bearings in automotive construction. Larger bearings need high strength and wear resistance, which established bearing materials cannot fulfill. Therefore, new alloy systems are required. This publication focuses on the influence of alloy composition and test temperature on the mechanical properties of ZnAlCu alloys. Centrifugally cast specimens were produced for the fabrication of test specimens, which were used to determine the mechanical and tribological properties. Fracture surface and wear trace analysis with scanning electron and light microscopy were used to determine occurring failure and wear mechanisms and to analyze the influence of microstructure on failure. Depending on the composition of the ZnAlCu alloys, up to three times higher strengths can be achieved compared with the white metal alloy SnSb12Cu6ZnAg. Furthermore, all the alloys investigated show good wear properties. Up to 11 wt.% aluminum and 1.5 wt.% copper, a significant decrease in the wear coefficient was observed. Knowledge about the correlation between microstructure, properties, and failure mechanisms of ZnAlCu alloys can be used to produce bearing metal alloys suitable for a wide range of applications. Since the strength values lie between those of white metals and bronze, new fields of application can also be accessed.

Effect of Al-Cu-Fe Quasicrystal Particles on the Reinforcement of a Polymer–Matrix Composite: From Surface to Mechanical Properties

We examined the effect of Al59Cu25Fe13B3 (at.%) quasicrystalline (QC) reinforcement particles on the mechanical and surface properties of a polymer-matrix composite by applying a technical polymer polyphthalamide (PPA). The observed increase in the tensile Young’s modulus ranged from 1810 MPa for the pure polymer to 4114 MPa for the composite with a QC filling of 35 vol.%. The elongation at fracture decreased with the filling fraction, being equal to 16.9% for a pure polymer and dropping to 4.8% for the composite with a QC filling of 35 vol.%. The same trend was noticeable with flexural Young’s modulus, which ranged from 100 MPa for a pure polymer to 125.5 MPa for the composite with 35 vol.% of QC. It was found that the increase in the mechanical strength led to a simultaneous increase of brittleness, which was reflected in a decrease of the impact strength for a pure polymer from 98.5 kJ/m2 to 42.4 kJ/m2 for composites with a QC filling of 35 vol.%. In contrast, when filled with 5 vol.% of QC, the impact strength increased by 8%. The friction coefficient against 100C6 steel dropped from 0.15 for pure PPA down to 0.10 for 5 vol.% of the QC filling, followed by an increase to 0.26 for further QC fillings up to 35 vol.%. Interestingly, a local minimum of friction was achieved at filling factors between 5 to 20 vol.% of QC. Independently, a clear surfenergy minimum was also found for the composite material with 20 vol.% of QC filling associated with a net drop in the polar component of the surfenergy. Surfenergy refers to the surface energy related to the top of the oxide layer under ambient conditions. We hypothesise that this is related to the percolation threshold at about 13 vol.% QC, reflected in the observed behaviour of both the friction coefficient and surfenergy. For the pure QC annealed in air for 1 h at 500 °C significant wear tracks were observed accompanied by a wear debris formation. On the other hand, a pure polymer exhibited slightly visible wear tracks with no apparent debris formation, and for the composites with different QC filling factors, the wear traces were barely visible with negligible debris formation.

The effect of temperature on the transfer layer of an aluminium alloy on tool steel and the effect of CrN coating

It is essential to explore temperature's crucial role while unveiling the intricacies of tribological interplay in CrN-coated steel-alloy systems. In the present study, tribological potential of CrN-coated hot-work tool steel was investigated under unidirectional single-pass sliding wear conditions. The sliding wear tests were performed at different temperatures (i.e., 20 °C, 100 °C, 200 °C, 300 °C, 400 °C and 500 °C) for the different sliding distances between 2 mm and 68 mm to explore the effect of temperature on the initiation and evolution of the transfer of an aluminium alloy (EN AW-6060). The effect was studied in terms of the contact area of the aluminium alloy and the volume transferred to the surface of the CrN. In addition, the structure of the wear trace and the equivalent friction coefficient were monitored with respect to the sliding distance and the temperature. The results show the strong dependency of the tribological potential of the CrN coating and the aluminium alloy on the temperature but show insignificant dependency on the sliding distance. When sliding up to 200 °C, the transfer was found to be dependent on the surface roughness of the coating, while strong adhesion led to the aluminium alloy's transfer during sliding at higher temperatures, that is, above 300 °C. At 500 °C, the CrN coating formed a self-protective Cr2O3 oxide that reduced the adhesive transfer of the alloy to the CrN compared to that at 200 °C–300 °C.

Early Upper Paleolithic Tubular Beads from the Main Chamber of Denisova Cave

The authors present the results of a technological and functional analysis of bone tubular beads from the Upper Paleolithic layer 11 in the Main Chamber of Denisova Cave, northwestern Altai. Tubular beads are among the most widespread categories of Early Upper Paleolithic ornaments from the cave. The technological sequence of operations has been reconstructed. It included several stages: selection of blank, planing, manufacture of preform by truncating the epiphyses, ornamenting the preform, marking preforms for fracturing into short tubes, sawing or cutting, fragmentation by cuts, removal of cancellous bone, and smoothing the fracture surfaces. Prepared blanks and diagnostic production waste were not noted in the technological context of the complex; this indicates that the tubular beads were probably manufactured outside the excavated area of the Main Chamber. The analyses revealed traces of wear caused by contact with clothing or human skin and by threading on a string or thin strap. Tubular beads were used by the Upper Paleolithic inhabitants of the cave as elements of clothing, necklaces, and probably bracelets. The closest but still considerably distant parallels to the tubular beads from the Altai are Aurignacian ornaments of a similar age from Western, Central, and Eastern Europe.

Экспериментально-трасологические исследования наконечников стрел в мезолите Горного Крыма

Traceological analysis of all microliths from multilayer sites Zamil-Koba 1 and 2, Alimovskiy rockshelter, Tash-Air 1, Kukrek revealed arrowheads of various types. Transverse arrowheads prevail in layers of the early phase of the Shan-Koba culture. Long segments and trapezes were used for this purpose. Oblique bladed arrowheads with a barb make a series. Long segments fixed in an oblique slot at the end of an arrow shaft were used as such arrowheads. Lanceolate points were used as piercing arrowheads which were met as single finds. Transverse arrowheads dominate at sites of the late phase of the Shan-Koba culture, while oblique bladed arrowheads with a barb are single. Upper layers of Alimovskiy rockshelter and Kukrek sites dated to the end of the Mesolithic produced only transverse arrowheads. Long trapezes and a small number of small long segments were used as such arrowheads. A number of experiments were carried out by the authors for verification of traceological definitions, research of behavior of different types of arrowheads when they hit the target and formation of various use-wear traces on arrowheads. Arrows were shot with bow at various targets. Experiments took place at Kholodnaya Balka in the Crimean Mountains in the suburb of Simferopol. Replicas of microliths from Mesolithic sites of the Crimean Mountains were used as arrowheads. Bow and arrow shafts were made of local hazel, dogwoods, buckthorn and pine. All stages of experiments were carefully documented. More than 500 shots were fired, and more than 50 arrowheads were used. As a result valuable data about behavior of arrowheads when hitting the target were obtained. Macro- and micro- wear traces on experimental replicas of arrowheads correspond well with traces on arrowheads singled out by the authors from studied collections of artefacts from Mesolithic sites of the Crimean Mountains and confirm validity of use-wear definitions.