Plastic Heat Research Articles

Modeling of Metal Cutting Processes Within the Material Point Method Using the Johnson–Cook Material Law

ABSTRACTThe material point method represents an alternative approach to simulations, differing from traditional methods like the finite element method (FEM). This technique involves discretizing bodies using material points while solving equations on a separate computational grid where each time step comprises three steps. Initially, the kinematic quantities of the material points are transferred to the grid nodes. Subsequently, computations are carried out on these nodes, with the results then reassigned to the material points, updating their position, velocity, stress as well as deformation state. After each time step, the previous grid is discarded as it does not rely on persistent information. As a result, a new grid is initialized in each time step, avoiding the risk of mesh distortion in the case of huge deformations, a common drawback arising in FEM analyses. This contribution presents simulations of three‐dimensional metal cutting processes utilizing the Johnson–Cook material law to accommodate for plastic strain rates and heat generated by plastic deformations. Additionally, the grid‐shift technique is employed to reduce oscillations and enhance robustness of the simulations.

Influence of Plastic Deformation and Heat Treatment on the Metallic Structure Control and Local Alloying: Example of Hot Shot Peening

Influence of Plastic Deformation and Heat Treatment on the Metallic Structure Control and Local Alloying: Example of Hot Shot Peening

Two-stage heat dissipation in plastic deformation of metals under ultra-high strain rate deformation

Understanding plastic heating at high strain rates is essential for designing material behavior. We employ molecular dynamics to analyze plastic heating and introduce a refined Taylor-Quinney coefficient (TQC) calculating approach. Our results reveal a two-stage heating behavior in high-strength systems, a relaxation stage characterized by rapid heating, stress relaxation, and increasing TQC, followed by a steady-state stage marked by linear temperature increase, constant stress, and stable TQC. The dislocation movement may behave as a plastic heating converter. During the relaxation stage, defect/dislocation nucleation dominates, leading to an increase in TQC as defect density rises upon yielding. Despite an increasing portion of plastic work being stored in defects, the data suggest that dislocations primarily act as sources of heat. In the steady-state stage, an unusual scenario emerges where defect density decreases as plastic deformation proceeds, yet TQC continues to increase due to the release of stored energy. This phenomenon is potentially explained by the annihilation of dislocation dipoles moving towards each other on the same slip plane. Additionally, TQC remains relatively insensitive to variations in temperature and strain rate over a broad range, challenging prior assumptions and expanding the understanding of plastic heating mechanisms.

Experimental Investigation into the Preparation Process of Graphene-Reinforced Aluminum Matrix Composites by Friction Stirring Processing.

Graphene has been considered an ideal reinforcement in aluminum alloys with its high Young's modulus and fracture strength, which greatly expands the application range of aluminum alloys. However, the dispersion of graphene and the interfacial reaction between graphene and the aluminum matrix limit its application due to elevated temperature. Friction stirring processing (FSP) is regarded as a promising technique to prepare metal matrix composites at lower temperatures. In this paper, FSP was used to prepare graphene-nanoplates-reinforced aluminum composites (GNPs/Al). The corresponding effects of the process parameters and graphene content on GNPs/Al were thoroughly studied. The results showed that plastic strain, heat input, and graphene content were the key influencing factors. Large degrees of plastic strain can enhance the dispersion of graphene by increasing the number of stirring passes and the ratio of stirring to welding velocity, thereby improving the strength of GNPs/Al. Low heat input restricts the plastic flow of graphene in the matrix, whereas excessive heat input can promote interfacial reactions and lead to the formation of a more brittle phase, Al4C3. This is primarily associated with the stirring velocity and welding velocity. High graphene content levels can improve the material strength by refining the grain size, improving the load transfer ability, and acting as a precipitate to prevent dislocation movement. These findings make a contribution to the development of advanced aluminum alloys with graphene reinforcement, offering broader application potential in industries.

An Optimized Strain-Compensated Arrhenius Constitutive Model of GH4169 Superalloy Based on Hot Compression.

A precise constitutive model is essential for capturing the deformation characteristics of the GH4169 superalloy in numerical simulations of thermal plastic forming processes. Hence, the aim of this study was to develop a precise modified constitutive model to describe the hot deformation behavior exhibited by the GH4169 superalloy. The isothermal cylindrical uniaxial compression tests of the GH4169 superalloy were carried out at temperatures of 950~1100 °C and strain rates of 0.01~10 s-1 using a Thermecmastor-200KN thermal-mechanical simulator. The original strain-stress curves were corrected by minimizing the effects of plastic heat and interfacial friction. Based on the true stress-strain curves, the original strain-compensated Arrhenius constitutive model was constructed using polynomial orders of 3, 5, and 10, respectively. The results showed that once the polynomial order exceeds the 5th, further increasing the order has little contribution to the accuracy of the model. To improve prediction ability, a higher precision Arrhenius constitutive model was established by extending a series of material parameters as functions that depend on temperature, strain, and strain rate, in which the error can be reduced from 4.767% to 0.901% compared with the classic strain-compensated Arrhenius constitutive model.

Simulation on the effect of filling porous medium on the performance of thermally conductive plastic heat sinks

High thermally conductive plastics have the characteristics of corrosion resistance, easy processing, and high thermal conductivity and can be used in corrosive environments or complex-shaped heat sinks. However, its thermal conductivity is still significantly lower than that of traditional metal heat sinks. Therefore, it is necessary to optimize the heat dissipation performance design. Based on the N–S equation and the k-ε turbulence model, the effect of porous media filled in the thermally conductive plastic heat sinks on its heat dissipation performance is studied. We compared this optimizing method with adding vortex generators in the literature. The maximum temperature of the heat sink bottom decreases by 9.3 °C. The pressure drop reduces by 55 %, and the Nusselt number increases by 9.3 %. The optimized heat sink has a hydrothermal performance factor (HTPF) 1.41. The heat dissipation performance can be similar to that of an aluminum heat sink. This study provides optimization ideas for expanding the application of thermally conductive plastics in heat sinks.

SIMULATOR BOILER HYBRID SEBAGAI FUNGSI PENGERING DAN PENGOLAH LIMBAH MEDIS JENIS PLASTIK

The hybrid boiler simulator is a simulation machine designed with two working functions, namely as a medical waste processing function and as a drying cabinet function. As a medical waste processor, this machine will focus on plastic medical waste, and as a dryer function, this machine will be a clothes-drying tool or cabinet. So based on the multifunctionality of the machine, this system has hybrid working characteristics. Hybrid boiler simulators can be a solution, providing the function of processing plastic medical waste and providing the advantageous function of economical and environmentally friendly drying. Therefore, this research aims to create a hybrid boiler simulator that can be used as a plastic medical waste processing machine and also as a clothes drying machine. The hybrid boiler system is designed by applying the concept of appropriate technology so that its implementation can be done easily and practically. The research implementation method is a classification of plastic medical waste, concept design, and analysis, construction design of a hybrid boiler system combined with an incinerator for burning medical waste, system function testing, and observation of test data. The focus of his research is the heat of burning plastic waste, heat radiation, circulators, and flow control systems as well as the characteristics of the results of burning plastic waste. The results of this research are that the hybrid boiler simulator machine can function as an incinerator machine to burn plastic medical waste and function as a clothes dryer; The function of the incinerator in this machine is only through two processes, namely the process of burning plastic medical waste raw materials and the process of burning carbon gas or smoke produced from the process of burning raw materials; the sumulator machine is not yet equipped with a fogging process for the function of smoke cleaning filter and fogging control; the hybrid boiler simulator machine works on the principle of automatic control based on temperature detection using a temperature sensor; The combustion temperature in the boiler machine can be controlled at a standard of 830 °C and the drying room temperature can be set at a room temperature of 50 – 150 °C.

Enhanced downstream processing of NGL using intensified fluid separation technologies

Downstream processing of natural gas liquids (NGL) provides feedstock needed for plastic production, upgraded fuels and heating, but it is one of the largest high-pressure and energy intensive processes. This original study is the first to integrate novel process intensification options from a holistic viewpoint for the full process covering all sections: 1) NGL recovery, 2) NGL fractionation, and 3) isomerization. Intensified fluid separation technologies (e.g. complex columns, thermal coupling, and heat pumps) are explored and integrated into a full NGL process to improve the energy efficiency and mitigate GHG emissions, and to establish the limits of operation, utility usage, and specific product costs. All NGL processes are rigorously simulated in Aspen Plus, and evaluated based on a fair economic and sustainability analysis.The enhanced recycle split vapor process for NGL recovery results in a full heat recovery for the reboiler of the demethanizer (2.9 MW energy savings), while the enhanced gas subcooled process results in 17.9% reduction of the refrigerant duty, 20.2% reduction of the electrical duty, and 19.9% reduction of the total utility cost. For the NGL fractionation section, heat pump assisted double dividing wall process improves energy intensity for a fraction of the utility cost although requiring external incentives (e.g., carbon tax) to become commercially viable. The total utility costs as well as GHG emissions are reduced up to 30% and 49%, respectively, while the specific product cost reduces to $23.45/t or $24.38/t with carbon tax. The heat pump assisted recycled isomerization process for the last section increased AKI from 65.3 to 89.6, with 19.1% reduction of utility usage and 42.4% reduction of carbon emission.

Top-down constitutive modelling to capture nanoscale shear localization

Deformation localization as exemplified by earthquakes, landslides, shear banding in solids, and failure of engineering components is of utmost importance. In practice, differentiating the mechanical behavior in such generative narrow bands from the rest part, with difference by orders of magnitude in characteristic size, flow strength, temperature, and shearing rate, is both experimentally and computationally formidable. Here we propose a machine-learning-based constitutive modeling framework to overcome this barrier borne from conventional top-down continuum modelling approach. The model enables us to realize ultra-fine resolutions for deformation in those narrow bands with high efficiency. Taking metallic glasses (MGs) as an example, our model captures well shear localization in BMGs across a broad range of temperatures (0 K to its melting point of ∼1000 K) and strain rates (10−4 to 108/s). We verify through this model the width of shear bands (SBs) in MGs is on the order of 5–8 nanometers, which is resulted from a cascade of (intervening) events, from localized shearing to plastic heating, subsequent temperature rise to thermal softening, and accelerated flow rate to strain-rate hardening. Temperature rise in SBs is a resultant of heat flow and plastic dissipation, but strongly depend on thermal conductivity: Low thermal conductivity facilitates strain localization and great temperature rise. It helps understanding the current controversy upon experimentally measured temperature rise ranging from several K to ∼1000 K. Lastly, strain rates within SBs are approximately one to two orders of magnitude higher than externally applied strain rates, and in general shearing in adiabatic SBs is faster than that in isothermal condition.

The Influence of Tempering Parameters on the Microstructure, Mechanical Property, and the Corresponding Strengthening Mechanism of Metastable 301 Austenitic Stainless Steel

Metastable austenitic stainless steels (MASS) are widely used in various industrial applications due to their exceptional mechanical properties. The microstructure of MASS can be regulated through severe plastic deformation, heat treatments, and surface treatments to achieve further improvement of mechanical properties. Herein, nanograin and quasiheterostructure are prepared by cold rolling and annealing process in Fe–17Cr–6Ni MASS. The mechanical response, deformation mechanism, and strengthening contribution of the two steels with representative microstructure are studied. The results indicate that nanograin austenitic steel (803 MPa, 22%) has superior yield strength and similar ductility compared with that of quasiheterostructure steel (600 MPa, 25%). In the nanograin steel, the deformation mechanism is mainly dislocation slip and deformation‐induced martensite transformation, while in quasiheterostructure steel, the deformation twinning is also included for the relative lower stacking fault energy in the coarse grain. The yield strength of nanograin structural steel is about 200 MPa higher than that of quasiheterostructure steel, which can be attributed to the differences in grain refinement strengthening, phase‐transformation strengthening, and precipitation strengthening of Cu particles. The findings presented in this study are informative for modulating MASS properties and ultimately improving the lifespan in a variety of industrial settings.

МЕТОДЫ МОДЕЛИРОВАНИЯ ТЕМПЕРАТУРЫ И ПЕРЕМЕЩЕНИЯ МАТЕРИАЛА ПРИ СВАРКЕ ТРЕНИЕМ С ПЕРЕМЕШИВАНИЕМ

Numerical modeling of the friction stir welding (FSW) process is challenging due to numerous complexities. This is a fully coupled thermomechanical problem that involves large plastic deformation, heat flow, nonlinear contact, and friction. Accurate modeling of the FSW process will provide a better understanding of the material flow and temperature distribution during the process, which is important for optimizing process parameters and reducing the likelihood of weld defects during FSW. Various approaches to modeling the temperature and material distribution in the FSW process are considered, such as the Euler or Lagrange approach, smoother particle hydrodynamics (SPH), coupled Euler and Lagrange methods (CEL), and arbitrary Lagrange and Euler methods (ALE). In this work, temperature and material distributions during the FSW process of a dissimilar aluminum-copper joint were simulated by finite element analysis using CEL and ALE approaches. In addition, it was shown that the temperature distribution along the weld line is asymmetrical: the maximum temperature on the advancing side is higher than on the retreating side.

Optimization of the Mechanical and Corrosion Resistance of Alloy 625 through Aging Treatments

In the as-annealed condition, the nickel-based Alloy 625 has excellent mechanical and corrosion properties compared to those of common stainless steels. This peculiarity enables its exploitation in several industrial fields at cryogenic and high temperatures and in the presence of severely corrosive atmospheres. However, in this alloy, when high-temperature plastic deformation processes and heat treatments are not carefully optimized, the occurrence of excessive grain coarsening can irremediably deteriorate the mechanical strength, possibly leading to incompatibility with the standard requirements. Therefore, this research work investigated the possibility of adopting single- and double-aging treatments aimed at improving such strength loss. Their optimization involved identifying the best compromise between the hardening effect and the loss in corrosion resistance induced by the simultaneous formation of intergranular chromium-rich carbides during aging. The investigation of the aging treatments was performed using hardness, tensile and intergranular corrosion tests considering different time–temperature combinations in a range from 621 °C to 732 °C. Double aging resulted in a considerable acceleration in the hardening response compared to single aging. However, even after its optimization in terms of both temperature and time, the intergranular corrosion resistance remained a critical aspect. Among all the tested conditions, only single aging at 621 °C for 72 h was acceptable in terms of both mechanical and corrosion properties. The influence of longer exposures will be investigated in a future study.

Microstructure, mechanical, electrical and wear properties of friction stir back extruded copper-6 vol.%Ti2SnC composite material

ABSTRACT This study investigates the impact of extrusion speed on the microstructure, mechanical and electrical properties, and wear resistance of friction stir back extruded Cu-6 vol.% Ti2SnC composite. The findings reveal that severe plastic deformation and heat generated during friction stir back extrusion (FSBE) of Copper-6 vol.% Ti2SnC composite prevented the formation of inter metallics at the particle-matrix interface and resulted in improved bonding. Increasing the speed from 45 to 85 mm/min reduced the maximum plastic strain from 65 to 48 and increased the strain gradient from the surface to the centre of the wire sample. The average grain size decreased from 7.6 ± 0.3 to 3.6 ± 0.2 µm and the average hardness increased from 121.59 ± 8.87 to 130.06 ± 9.95 HV. The yield strength, ultimate tensile strength and elongation decreased by 5.6%, 24% and 12.7% respectively. Wires obtained at the reduced speed of 45 mm/min exhibited an increase of 13% and 26% in electrical conductivity and wear resistance respectively relative to those of the copper matrix material. Analysis of results in the light of a few models indicate that they are in conformity with the results of some of them.

Possibility of High Ionic Conductivity and High Fracture Toughness in All-Dislocation-Ceramics.

Based on the results of numerical calculations as well as those of some related experiments which are reviewed in the present paper, it is suggested that solid electrolytes filled with appropriate dislocations, which is called all-dislocation-ceramics, are expected to have considerably higher ionic conductivity and higher fracture toughness than those of normal solid electrolytes. Higher ionic conductivity is due to the huge ionic conductivity along dislocations where the formation energy of vacancies is considerably lower than that in the bulk solid. Furthermore, in all-dislocation- ceramics, dendrite formation could be avoided. Higher fracture toughness is due to enhanced emissions of dislocations from a crack tip by pre-existing dislocations, which causes shielding of a crack tip, energy dissipation due to plastic deformation and heating, and crack-tip blunting. All-dislocation-ceramics may be useful for all-solid-state batteries.

Special at-rich sequence-binding protein 2 and its role in healing of the experimental mandible bone tissue defect filling with a synthetic bone graft material and electrical stimulation impact.

Aim: The purpose of the study was to identify the role of SATB2 in healing of the experimental mandible bone tissue defect filling with a synthetic bone graft material and electrical stimulation impact. Materials and Methods: An experiment was carried out on 48 mature male rats of the WAG population, which were divided into 4 groups. Each group included 12 experimental animals. Group 1 included rats that were modeled with a perforated defect of the lower jaw body. Group 2 included animals that were modeled with a perforated defect similar to group 1. In animals, a microdevice for electrical action was implanted subcutaneously in the neck area on the side of the simulated bone defect. The negative electrode connected to the negative pole of the battery was in contact with the bone defect. The battery and electrode were insulated with plastic heat shrink material. Group 3 included rats that were modeled with a perforated defect similar to previous groups, the cavity of which was filled with synthetic bone graft "Biomin GT" (RAPID, Ukraine). Group 4 included animals that were modeled with a perforated defect similar to groups 1-3, the cavity of which was filled with synthetic bone graft "Biomin GT" (RAPID, Ukraine). The simulation of electrical stimulation was the same as in group 2. The material for the morphological study was a fragment of the body of the lower jaw from the zone of the perforated defect. Immunohistochemical study was performed using rabbit anti-human SATB2 monoclonal antibody. Results: In the regenerate filling the defect in the bone tissue of the lower jaw of rats, there was an increase in SATB2 expression under conditions of electrical stimulation; filling the defect with a synthetic bone graft material; simultaneous filling the defect with a synthetic bone graft material and electrical stimulation. The most pronounced expression of SATB2 was observed under conditions of simultaneous filling the defect with a synthetic bone graft material and electrical stimulation; minimally expressed - in conditions of filling the defect with a synthetic bone graft material; moderately expressed - under conditions of electrical stimulation. In the regenerate, in cases of all treatment methods, SATB2 was expressed by immune cells, fibroblastic differon cells, osteoblasts, and in case of electrical stimulation, also by adipocytes, vascular pericytes and endothelial cells, epidermis. Conclusions: The activation of SATB2 expression identified by the authors is one of the mechanisms for stimulating reparative osteogenesis under the conditions of electrical stimulation; filling the defect with a synthetic bone graft material; simultaneous filling the defect with a synthetic bone graft material and electrical stimulation.

Insight on ultrasonic effect of Al[sbnd]Cu aluminum alloy joints fabricated by ultrasonic assisted non-thinning and penetrating friction stir welding

AlCu alloy joints of ultrasonic assisted non-thinning and penetrating friction stir welding (U-NTPFSW) and NTPFSW were prepared. The microstructure and mechanical properties of the joints were studied comparatively to elucidate the effect of ultrasonic. This study provided an in-depth understanding of the microstructure formation mechanism and strengthening mechanism of joints under the ultrasonic effect. Ultrasonics broadened the width of the stir zone (SZ) and stationary shoulder affected zone (SSAZ) by promoting the material plastic flow ability and changing the material flow at the weld root. The ultrasonic addition enhanced plastic heat production and promoted grain growth in SZ. Compared with NTPFSW, the SZ of both joints was dominated by continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX) mechanisms, and geometric dynamic recrystallization (GDRX) grains were also present in U-NTPFSW. The mechanical properties of the joint were improved from 339 MPa to 348 MPa. Ultrasonics introduced numerous vacancies into the weld, which promoted the precipitation of the Al2Cu phase and increased the precipitated phase density of the thermal-mechanical affected zone (TMAZ). The interaction mechanism between the precipitated phase and dislocations was analyzed. The geometrically necessary dislocation (GND) density and residual stress of TMAZ were reduced due to ultrasonic vibration.

Enhancing the strength of Sc-containing Al-Cu-Li alloys by modifying the precipitation behavior through plastic deformation and heat treatment

Al-Cu-Li alloys are used extensively in the aerospace manufacturing industry for their outstanding properties, however, the addition of trace Sc elements will form high-temperature insoluble (Cu, Sc)-containing phases during homogenization leads to a decrease in age-strengthening, and there is a limited investigation on how to overcome this unfavorable factor. In this work, the effects of plastic deformation coupled with heat treatment on the microstructure and mechanical properties of Sc-containing Al-Cu-Li alloy were systematically investigated by using age-hardening curves and room-temperature tensile tests combined with characterization by TEM, EBSD, and SEM/EDS. The results show that plastic deformation before high-temperature treatment fragments and promotes the dissolution of coarse phases, reduces the development of (Cu, Sc)-containing enriched phases, and simultaneously increases the content of Cu atoms within the Al matrix. Among all precipitates (GPB zones, S phases, T1 phases) after T6 aging, T1 phases act as the dominant strengthening phase of the alloy. At the same time, we found that the decrease in the Cu-containing residual phase after solid solution treatment will result in a remarkably increasing number density and volume fraction of T1 phases at the peak aging. In a word, we obtain a good strength-ductility trade-off (the yield strength is ∼500 MPa while maintaining ∼10% elongation) Al-Cu-Li alloy with Sc element by optimizing the distribution of Cu elements and modulating the aging precipitation behavior. Our proposed process is expected to provide an experimental and theoretical guide toward the development of Al-Cu-Li alloys with superior properties.

Cooling-assist friction stir welding: A case study on AA6068 aluminum alloy and copper joint

This study evaluates the impact of cooling-assist friction stir welding (CA-FSW) tool rotational and traverse velocities on the bonding quality of Al-Cu-Mg and copper lap joints. A modified computational fluid dynamics (CFD) technique analyzes heat generation and distribution during dissimilar CA-FSW joints between AA6068 alloy and copper. The relationship between CA-FSW tool velocities and metallurgical properties of the final joint is assessed. Simulation results provide insights into metallurgical phenomena during the CA-FSW process. Findings reveal greater plastic deformation and heat generation on the AA6068 aluminum alloy side due to raw material placement, resulting in more significant microstructure changes in AA6068 aluminum alloy compared to copper. Increased heat generation leads to higher copper-rich intermetallic compound (IMC) formation, resulting in increased hardness of the stir zone at the base metals’ interface.

Investigation on the Optimal Amount of Y and B Elements in High-Temperature Titanium Alloy Ti-5.9Al-4Sn-3.9Zr-3.8Mo-0.4Si-xY-yB

This article presents a novel and feasible approach for researching the quantity of the ceramic phase and component optimization in high-temperature titanium alloys with small trace amounts of ceramic phases. Different near-α titanium alloys with varying yttrium and boron contents were prepared through the utilization of a vacuum non-consumable arc furnace melting method. The alloy used was a Ti-5.9Al-4Sn-3.9Zr-3.8Mo-0.4Si base. Its microstructure, texture, mechanical properties, and fracture behavior were studied. The observation of the as-cast structure shows that the addition of different doses of trace Y and B elements significantly refines both the original β grains and α grains. Moreover, the addition of the B element transforms the Widmanstätten structure in the titanium alloy structure into a basketweave structure. The addition of Y can refine the grain structure, improve the uniformity of the matrix structure, and act as a strong deoxidizer, which will take away the oxygen in the matrix and purify it. The TiB whiskers generated with the addition of B promotes dynamic recrystallization behavior and leads to more equiaxed α grains being precipitated around them, resulting in a significant refinement of the microstructure of the as-cast alloy. After adding a small amount of B, the texture strength of the α phase is significantly reduced, indicating that TiB whiskers inhibit the formation of texture. After conducting performance screening and structure analysis, the study supplements the analysis of Y’s regulation of the titanium alloy structure. The regulation is primarily explained by combining the results of the analysis of boron content, phase diagram analysis, mechanical properties, and fracture analysis. The mechanical analysis introduces the unique load transfer strengthening of TiB whiskers combined with an analysis of high-temperature mechanical properties, as the threshold for addition. The optimal amounts of Y and B additions are 0.6 wt% and 0.8 wt%, respectively. The optimized alloy obtained under this condition can achieve a tensile strength of 950 Mpa at 500 °C without any plastic deformation or heat treatment.

Trimethyltin chloride exposure induces apoptosis and necrosis and impairs islet function through autophagic interference

Trimethyltin chloride (TMT) is a highly toxic organotin compound often used in plastic heat stabilizers, chemical pesticides, and wood preservatives. TMT accumulates mainly through the environment and food chain. Exposure to organotin compounds is associated with disorders of glucolipid metabolism and obesity. The mechanism by which TMT damages pancreatic tissue is unclear. For this purpose, a subacute exposure model of TMT was designed for this experiment to study the mechanism of damage by TMT on islet. The fasting blood glucose and blood lipid content of mice exposed to TMT were significantly increased. Histopathological and ultrastructural observation and analysis showed that the TMT-exposed group had inflammatory cell infiltration and necrosis. Then, mouse pancreatic islet tumour cells (MIN-6) were treated with TMT. Autophagy levels were detected by fluorescence microscopy. Real-time quantitative polymerase chain reaction and Western blotting were used for verification. A large amount of autophagy occurred at a low concentration of TMT but stagnated at a high concentration. Excessive autophagy activates apoptosis when exposed to low levels of TMT. With the increase in TMT concentration, the expression of necrosis-related genes increased. Taken together, different concentrations of TMT induced apoptosis and necrosis through autophagy disturbance. TMT impairs pancreatic (islet β cell) function.