Crystallization Curves Research Articles

Coupling theoretical analysis and FE framework for revealing the size effect on the deformation characteristics of 304 stainless steel microtubes manufactured via free-bending forming technology

The current study on free bending focuses on traditional macroscopic tubes and profile components. Nevertheless, as the geometric size of the tube decreases, the resulting size effect affects the free bending deformation behavior of the microtube in the less constrained state. In this investigation, a constitutive model of microtubes considering the surface layer model was established. The corresponding model parameters were determined by fitting the flow curves of surface single crystals and internal polycrystals. According to the principle of free bending, the springback internal bending moment of the microtube was derived to explain the phenomenon whereby the bending radius of the microtube decreases with decreasing size factor. With decreasing size factor, the influence of the surface layer grains on the bending behavior of the microtube becomes more intense. Furthermore, by comparing the results of the microscale free bending experiment and simulation, it can be concluded that the material properties of microtubes in the finite element (FE) simulation should be defined based on the surface layer and inner layer. With decreasing microtubule size factor, the bending radius of the tube decreases, and the wall thickness changes more significantly. The cross-sectional distortion of the microtubes decreases with increasing grain size and wall thickness. This study explored the feasibility of the free bending process to achieve bending of microtubes and revealed that the size effect on the deformation behavior of microtubes should be considered in the microscale free bending process.

Enhanced electrical properties of pulsed Sn-doped (-201) β-Ga2O3 thin films via MOCVD homoepitaxy

Pulsed Sn doping (PSD) homoepitaxial gallium oxide (Ga2O3) films were deposited on (-201) β-Ga2O3 substrates using metal-organic chemical vapor deposition (MOCVD). The study aims to optimize Sn doping conditions to enhance the electrical properties of β-Ga2O3 films. The influence of Sn pulse width (ranging from 0.1 min to 0.3 min) on the morphology, structure, and electrical properties of the film was investigated. The Full Width at Half Maximum (FWHM) of the (-201) crystal plane rocking curve for all doped films is <50 arcsec, indicating high crystal quality. At a Sn pulse width of 0.2 min, we achieve the optimal balance between doping efficiency and crystal quality, resulting in a resistivity of 0.0487 Ω·cm, an electron mobility of 63.5 cm2/V·s, and a carrier concentration of 1.82 × 1018 cm-3. Compared to continuous Sn doping, PSD results in approximately 157 % increase in carrier concentration and 99 % increase in electron mobility. The application of PSD allows sufficient diffusion time for Sn atoms to effectively incorporate into the film, signifying a crucial advancement in enhancing the film's electrical properties and reducing the cost of the metal organic doping source.

Crossover from Relativistic to Non-Relativistic Net Magnetization for MnTe Altermagnet Candidate

We experimentally study magnetization reversal curves for MnTe single crystals, which is the altermagnetic candidate. Above 85 K temperature, we confirm the antiferromagnetic behavior of magnetization M, which is known for α-MnTe. Below 85 K, we observe anomalous low-field magnetization behavior, which is accompanied by the sophisticated \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M(\\alpha )$$\\end{document} angle dependence with beating pattern as the interplay between \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M(\\alpha )$$\\end{document} maxima and minima: in low fields, \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M(\\alpha )$$\\end{document} shows ferromagnetic-like 180° periodicity, while at high magnetic fields, the periodicity is changed to the 90° one. This angle dependence is the most striking result of our experiment, while it can not be expected for standard magnetic systems. In contrast, in altermagnets, symmetry allows ferromagnetic behavior only due to the spin–orbit coupling. Thus, we claim that our experiment shows the effect of weak spin–orbit coupling in MnTe, with crossover from relativistic to non-relativistic net magnetization, and, therefore, we experimentally confirm altermagnetism in MnTe.

Composition, thermal, and microstructural characteristics of mutton tallows in comparison with beef tallows

AbstractThe composition, thermal properties, and microstructure of some mutton tallows (MTs), such as sheep tallow (ST), goat tallow (GT), and sheep tail tallow (STT), were investigated and compared with those of beef tallow (BT). The results showed that the fatty acids (FAs) in the MTs were dominated by oleic, stearic, and palmitic acids, which were similar to those of BTs; also there were some natural trans and odd‐carbon FAs occurred in these tallows. Comparison with STs, GTs, and BTs, STT had higher triunsaturated and diunsaturated‐monosaturated triacylglycerols (TAGs) and lower monounsaturated‐disaturated and trisaturated TAGs. Solid fat content (SFC) profile of STT was different those of STs, GTs, and BTs, whereas STs, GTs, and BTs had similar SFC profiles. In the range of 0–50°C, STT had a lower SFC compared with STs, GTs, and BTs at a given temperature. DSC results showed that MTs had melting and crystallization curves similar to BTs; and the GT, ST, and BT had higher melting and crystallization temperatures than STT. All MT and BTs crystals are β′ form; there also exists certain β form. The microscopic morphology of the STT was radial spherical aggregates, and those of other MT and BTs were consisted of radial inner core and low density outer halo area.Practical Application: The results of SFC, microstructure, and morphology indicated mutton tallows containing the desired crystal form and crystal morphology could be used as shortening base fats. The research can provide a theoretical basis for expanding the application of mutton tallows in food industry.

Deep learning of plausible bandgaps in dispersion curves of phononic crystals

Phononic crystals represent an interesting class of metamaterials that can be utilized to regulate or manipulate vibration, sound propagation, and thermal transport. Their useful features mainly arise from the bandgaps in their dispersion curves, preventing the passage of waves within specific frequency ranges. However, it is often costly and time-consuming to obtain the dispersion curves, and the reverse engineering of phononic crystals to have pre-defined bandgaps possesses even greater challenges. In this research, we address this issue by employing a deep artificial neural network to predict the bandgap ratio and the characteristics of plausible bandgaps, focusing on the localized resonance in columnar phononic crystals. We utilized two geometric parameters, i. e. the ratio of diameter and height of the cylindrical resonators relative to the lattice constant, achieving a determination coefficient of 0.9993 for predicting the characteristics of the bandgaps and 0.9827 for predicting the bandgap ratio. To verify the model and better understand its behavior, we introduce Shapley values. These values provide a comprehensive insight into how each geometric parameter influences the predicted bandgap ratios.

Crossover from relativistic to non-relativistic net magnetization for MnTe altermagnet candidate

Abstract We experimentally study magnetization reversal curves for MnTe single crystals, which is the altermagnetic candidate. Above 85 K temperature, we confirm the antiferromagnetic behavior of magnetization M, which is known for α–MnTe. Below 85 K, we observe anomalous low-field magnetization behavior, which is accompanied by the sophisticated M(α) angle dependence with beating pattern as the interplay between M(α) maxima and minima: in low fields, M(α) shows ferromagnetic-like 180° periodicity, while at high magnetic fields, the periodicity is changed to the 90° one. This angle dependence is the most striking result of our experiment, while it can not be expected for standard magnetic systems. In contrast, in altermagnets, symmetry allows ferromagnetic behavior only due to the spin-orbit coupling. Thus, we claim that our experiment shows the effect of weak spin-orbit coupling in MnTe, with crossover from relativistic to non-relativistic net magnetization, and, therefore, we experimentally confirm altermagnetism in MnTe.

Numerical investigation of effective nonlinear coefficient model for coupled third harmonic generation

In this paper, the optimal solution of effective nonlinear coefficient of quasi-phase-matching (QPM) crystals for coupled third harmonic generation (CTHG) was numerically investigated. The effective nonlinear coefficient of CTHG was converted to an Ising model for optimizing domain distributions of aperiodically poled lithium niobate (APPLN) crystals with lengths as 0.5 mm and 1 mm, and fundamental wavelengths ranging from 1000 nm to 6000 nm. A method for reconstructing crystal domain poling weight curve of coupled nonlinear processes was also proposed, which demonstrated the optimal conversion ratio between two coupled nonlinear processes at each place along the crystal. In addition, by applying the semidefinite programming, the upper bound on the effective nonlinear coefficients deff for different fundamental wavelengths were calculated. The research can be extended to any coupled dual χ(2) process and will help us to understand better the dynamics of coupled nonlinear interactions based on QPM crystals.

Improvement of crystallinity of CdZnTe epilayers on GaSb substrates by ZnTe buffer layer

Thick CdZnTe epitaxial film is a promising alternative for X-ray detectors, especially in the case of large-area imaging application. One of the key issues in growing thick heteroepitaxial film with high crystallinity is to reduce the mismatch dislocations that appear at the interface between CdZnTe epilayer and the substrate. In this paper, we prepared CdZnTe films without and with ZnTe buffer layers on GaSb (001) substrates by the closed space sublimation. All preparation conditions for ZnTe buffer layers, CdZnTe epilayers on ZnTe buffers and GaSb substrates, as well as the pretreatment of GaSb surface have been optimized through tremendous experiments. The results of electron backscatter diffraction and transmission electron microscope observation prove that ZnTe buffer layers suppress (1‾1‾1)M twins extending from GaSb. The deposition temperature for inserting ZnTe buffer about 495 K is optimized for getting smooth ZnTe surface, on which high crystalline quality CdZnTe epilayer with a narrower full-width at half-maximum (85 arcsec) of double crystal X-ray rocking curve for (004) reflection and lower intensity ratio IDcomplex/I(D0, h) of low-temperature photoluminescence spectroscopy were produced.

Energy transfer and photoluminescence properties of CaYGaO4:Bi3+,Tb3+ phosphors

Trivalent bismuth and trivalent terbium ions doped CaYGaO4 were prepared. The crystal structure, phase purity, photoluminescence, decay curves, and emission spectra under various temperatures were investigated. The six-coordinate Ca2+ and Y3+ ions are occupied by Bi3+ ions, while Tb3+ ions take up the six-coordinate Y3+ ions in the CaYGaO4:Bi3+,Tb3+ phosphor. The emissions of trivalent bismuth (3P1 → 1S0) and trivalent terbium ions (5D4 → 7F5) excited by 320 nm were observed. The analysis of spectra and decay curves demonstrated that Bi3+ could transfer energy to Tb3+ via electric dipole-quadrupole interaction. By altering the concentration of trivalent terbium ions, the emitting color of phosphor was tuned from blue to green. The temperature sensing property of CaYGaO4:Bi3+,Tb3+ was described, and its relative sensitivity at 303 K achieves a maximum of 0.61% K−1. According to the results, CaYGaO4:Bi3+,Tb3+ is a potential material for color tunable emission and temperature sensing.

An alternative post-processing of transient liquid crystal experiments using the wall temperature gradient time response

An alternative method for the fast evaluation of transient liquid crystal experiments is presented in this study. The calibration of liquid crystals has been considered essential to obtain accurate heat transfer measurements. Nevertheless, liquid crystal aging, illumination, and ex situ calibration effects remain a difficult and might influence the heat transfer level. Proposed here is to bypass liquid crystal calibration by utilizing the evolution of the wall temperature gradients. This necessitates the use of the detection times of the maximum red and green intensities of narrow bandwidth liquid crystals, e.g., less than 1 K, whose temperature span is on the order of 0.3 K. The calculation of the heat transfer coefficients can be thus feasible by differentiating the wall temperature from the solution of the semi-infinite body approach with respect to time. This approach is examined over different experiments with varying geometries and liquid crystal detection times. The in-advance possession of the calibration curves of the liquid crystals allows for the method’s cross-evaluation. The results indicate that the proposed method is in sufficiently good agreement with the values obtained using the calibrated liquid crystal signals. In particular, the average heat transfer coefficient of a surface is within 8% from the traditional method which is sufficient for industrial applications and preliminary thermal designs.

Revealing the adhesion, stability, and electronic structure of SiC/M (M=Au, Pt) interface: A first-principles study

The interface bonding and electronic properties between SiC and metal are the key factors affecting the physical transport phenomena of metal-semiconductor field-effect transistors (MESFETs). The work of adhesion, interface energy and electronic structure of SiC/M (M = Au, Pt) interface are explored by first-principles method. Forty possible interface models were constructed for different surfaces and stacking positions, and the four most stable interfaces were screened based on the work of adhesion and interface energy. Moreover, the interfacial bonding behavior and strength of SiC/M were quantitatively and qualitatively described through partial density of states (PDOS), crystal orbital Hamilton population curves (COHP), and charge density distribution (CDD). The PDOS demonstrated covalent bond characteristics between M − Si and M − C, which are primarily bonded by M-d and Si-p or C-p orbital hybridization. Further, the COHP and CDD analyses clearly manifested that the Pt–C bond at the interface exhibits more pronounced electron aggregation and greater bonding strength than the Au–C bond. This study offers a comprehensive understanding of the interfacial bonding strength between SiC and Au or Pt and demonstrate that SiC/Pt contact is the more favorable option for electronic device materials.

Study of the Crystal Architecture, Optoelectronic Characteristics, and Nonlinear Optical Properties of 4-Amino Antipyrine Schiff Bases.

Two Schiff bases, (E)-4-((2-chlorobenzylidene)amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (4AAPOCB) and (E)-4-((4-chlorobenzylidene)amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (4AAPPCB), have been synthesized and grown as single crystals. Single-crystal X-ray diffraction analysis was employed to determine the crystal structure of the compounds, and the results suggest that the compounds crystallized into an orthorhombic crystal system having P212121 and Pbca space groups, respectively. Further, the crystallinity of the compounds was analyzed by the PXRD technique. The UV-vis-NIR spectra of the compounds demonstrate excellent transmittance in the entire visible region. The lower cutoff wavelengths of the compounds were determined to be 338 and 333 nm, respectively; additionally, optical band gaps of the compounds found were 4.60 and 4.35 eV. FTIR and NMR (1H and 13C) spectral techniques were utilized to analyze the molecular structure of the compounds. The compounds emit photoluminescence with broad emission bands with centers at 401 and 418 nm. The thermal stability and phase transitions were assessed through thermogravimetric methods. The phase transition prior to melting was indicated by the endothermic event at around 190 °C in the DTA curves of both crystals, and the same was observed in the DSC curves. The second harmonic efficiencies of the powdered compounds I and II were found to be 3.52 and 1.13 times better than that of the standard reference KDP. The 4AAPOCB and 4AAPPCB compounds showed isotropic polarizability amplitudes of 46.02 × 10-24 and 46.52 × 10-24 esu, respectively. The calculation of linear polarizability and NLO second-order polarizability (β) along with other optical parameters was performed for optimized geometries. The nonzero amplitudes of the average β values for compounds 4AAPOCB and 4AAPPCB were found to be 14.74 × 10-30 and 8.10 × 10-30 esu, respectively, which show a decent potential of the synthesized molecules for NLO applications. The calculated β amplitudes were further explained based on calculated electronic parameters like molecular electrostatic potentials, frontier molecular orbitals, molecular orbital energies, transition energies, oscillator strengths, and unit spherical representation of NLO polarizability. The current analysis emphasizes the significance of synthesized compounds as prospective candidates for optical and NLO applications through the use of experiments and quantum computations.

Direct comparison between experiments and dislocation dynamics simulations of high rate deformation of single crystal copper

A long standing challenge in computational materials science is to establish a quantitative connection between the macroscopic properties of plastic deformation with the microscopic mechanisms of dislocations in crystalline materials. Although the discrete dislocation dynamics (DDD) simulation method has been developed for several decades with the goal of addressing this challenge, a one-to-one comparison between the DDD predictions on single crystal stress–strain curves and experimental measurements under identical conditions has not been possible to date. Such a comparison is an essential step towards establishing a dislocation-physics based theory of plasticity and a multiscale framework of the plastic behaviors of crystalline materials. Here we provide direct comparisons between the stress–strain curves of Cu single crystals under high strain rate loading in the [001] and [011] directions obtained from miniaturized desktop Kolsky bar experiments and those from DDD simulations under identical loading conditions. With an appropriate set of parameters, DDD simulations can produce stress–strain curves that are in reasonable agreement with the experimental results. However, the dislocation mobility values needed to achieve this agreement are an order of magnitude lower than expected based on previous measurements and atomistic simulations. We hypothesize that this discrepancy could be caused by drag forces from jogs and point defects produced during the plastic deformation. Cross-slip of screw dislocations is also found to be necessary to capture the experimental stress–strain behavior, especially for the [011] loading direction. This work provides an example of how direct comparisons between DDD simulations and experimental measurements can provide new insight into the fundamental mechanisms of plastic deformation.

Mesoscale slip behavior in single crystal and bicrystal tantalum

Single-crystal and bicrystal tensile specimens of various orientations were prepared from coarse-grained, pure Ta to investigate fundamental BCC slip behavior at the mesoscale, that is, without considering discrete dislocation mechanisms. Single crystal yield behavior was well-represented by concurrent {110} and {112} slip modes with the initial CRSS for {110} 6% lower than for {112}. A new metric quantitatively representing slip multiplicity in a crystal visco-plastic context was introduced. Initial strain hardening correlates positively with this “activity index” tending to confirm the dominant role of latent hardening in single crystals. Anelastic hysteresis at least as significant as in polycrystal/polyphase alloys was observed, with loop width increasing with pre-strain rather than solely with flow stress as previously supposed. Tensile tests of “triplets” consisting of a bicrystal specimen and its two constituent single crystal specimens revealed the differential effects of grain boundaries (GB) on strength and anelastic hysteresis. Two triplets followed the rule-of-mixtures (ROM); two triplets showed synergistic strength and anelasticity. Crystal plasticity (CP) simulations with two slip modes having different hardening behaviors predicted the single crystal stress-strain curves reasonably for various orientations. Plastic deformation incompatibility was identified as the likely source of deviation from rule-of-mixture behavior. CP simulations predicted the appearance of additional slip systems near the GBs in the synergistic triplets, but did not predict the observed strength and anelastic hysteresis.

Metal Crystal/Polycrystal Plasticity and Strengths

A brief historical sketch is given of Taylor’s dislocation density-based model description, leading to the prediction of a parabolic, tensile, stress–strain curve for the plastic deformation of aluminum. The present focus is on additional results or analyses obtained on the subject for crystal/polycrystal strain hardening. Our current understanding of such material behavior is attributed to post-Taylor descriptions of sequential deformation stages in stress–strain measurements that are closely tied to specific dislocation interaction and reaction mechanisms. A schematic comparison is given for individual face-centered cubic (fcc), body-centered cubic (bcc), and hexagonal close-packed (hcp) crystal curves and to related strength properties determined for individual crystals and polycrystalline material. For the fcc case, an example sessile dislocation reaction is described based on a stereographic projection. Then, quantitative constitutive-relation-based assessments are presented for the tensile strain hardening leading to the plastic instability behaviors of copper and tantalum materials.

Changes in Chemical Composition of Flaxseed Oil during Thermal-Induced Oxidation and Resultant Effect on DSC Thermal Properties.

To investigate the changes in chemical composition of flaxseed oil during thermal-induced oxidation and the resultant effect on thermal properties, samples with different oxidation levels were obtained by being heated at 180 °C for two hours and four hours. The oxidation degree was evaluated using peroxide value (PV), extinction coefficient at 232 nm and 268 nm (K232 and K268), and total polar compounds (TPC). Using chromatography, the fatty acid profile and triacylglycerol (TAG) profile were examined. Differential scanning calorimetry (DSC) was used to determine the crystallization and melting profiles. Thermal-induced oxidation of flaxseed oil led to a significant increase (p < 0.05) in PV, K232, K268, and TPC, but the relative content of linolenic acid (Ln) and LnLnLn reduced dramatically (p < 0.05). TPC derived from lipid degradation affected both crystallization and melting profiles. Statistical correlations showed that the onset temperature (Ton) of the crystallization curve was highly correlated with K232, TPC, and the relative content of LnLnLn (p < 0.05), whereas the offset temperature (Toff) of the melting curve was highly correlated with the relative content of most fatty acids (p < 0.05). This finding provides a new way of rapid evaluation of oxidation level and changes of chemical composition for flaxseed oils using DSC.

Crystal plasticity finite element modeling of twin band formation and evolution together with the macroscale mechanical responses of hexagonal metals

Deformation twinning is one of the major plastic deformation modes of hexagonal metals. In this study, a new system of crystal plasticity finite element models is developed, with the cooperative interactions of dislocation slip and deformation twinning comprehensively involved. The obtained stress-strain curves for several differently-orientated Mg single crystals match well with experimental results, and the formation and thickening features of twin bands are captured. Simulation results reveal that (1) some thin twin bands are firstly formed in the shearing direction of the twinning plane, because of the much lower twinning resistance than that in the normal direction; (2) the softening and hardening of the twinning resistance play a critical role in the anisotropic mechanical response. By optimizing the twinning activation behaviors, the favorable interactions of twinning and dislocation slip can occur and the plastic deformation ability can be improved.

Rare earth metal‐doped Zintl phase thermoelectric materials: The Yb5−xRExAl2Sb6 (RE=Pr, Nd, Sm) system

AbstractThree Zintl phase solid solutions in the Yb5 − xRExAl2Sb6 (RE = Pr, Nd, Sm) system have successfully been synthesized by arc melting followed by annealing. The isotypic crystal structure of these compounds was characterized by PXRD and SXRD analyses, and their Ca5Al2Bi6‐type structure (space group Pbam, Z = 2) was described as a combination of (1) the 3‐dimensional anionic [Al2(Sb4Sb4/2)] frameworks and (2) the space‐filling cations Yb2+ and RE3+ located in between the anionic frameworks. In particular, the anionic frameworks were originally built from the two neighboring tetrahedral [AlSb4] moieties via the Sb1‐Sb1 bridges. The site‐preference of RE3+ for the Yb3/RE‐site with the mixed occupation ratio between ca. 9% and 16% of RE3+ was elucidated by the size‐factor criterion based on the size match between the cationic size and the site volume. The band structures, density of states, and crystal orbital Hamilton population curve analyses were conducted by the tight‐binding linear muffin‐tin orbital method, and the results proved that the RE3+‐doping increased the band degeneracies and the number of resonance peaks near the Fermi level resulting in the improved Seebeck coefficients. The electrical transport property measurements proved that despite the successful addition of n‐type RE3+ dopants in the title Yb5 − xRExAl2Sb6 system, the electrical conductivity decreased due to the canceling off of the newly added n‐type carriers by the already existing p‐type carriers resulting in still the p‐type character. However, the enhanced Seebeck coefficients predicted by the increased effective mass from the DFT calculations eventually improved the overall power factor of the RE3+‐doped title compounds.

In situ X‐ray Scattering of the Crystallisation of Basic Magnesium Chlorides using a Laboratory Instrument

AbstractWe demonstrate a method for in situ monitoring of the crystallisation of basic magnesium chlorides using a laboratory‐based SAXS (small angle X‐ray scattering)/ WAXS (wide angle X‐ray scattering) instrument. By simultaneous acquisition of SAXS/WAXS, time‐resolved particle size and phase evolution information was obtained from room temperature to 120 °C. The WAXS data were analysed using two‐phase Rietveld refinements, to produce crystallisation curves. From Avrami‐type kinetic analysis two competing mechanistic processes were proposed for the formation of Mg3Cl(OH)5 ⋅ 4 H2O with a nucleation‐type mechanism extending further into the reaction with increased temperature. When comparing SAXS and WAXS, an offset between the consumption of MgO and the reduction of the sphere contribution to the SAXS scattering is observed. This is rationalised by the formation of an amorphous Mg(OH)2 layer on the MgO particle surface. Although laboratory‐based SAXS/WAXS instruments have limitations compared to synchrotron‐based sources, we have demonstrated how they can provide new insights into the formation of materials.

Customization of novel double-perovskite (Ca,Sr)2InNbO6:Mn4+ red-emitting phosphors for luminescence lifetime thermometers with good relative sensing sensitivity

Luminescent thermometry with some outstanding advantages of quick response, large measurement range, and good sensing sensitivity has been widely investigated and suggested for practical applications as a kind of potential technique to detect real temperature. Herein, novel double-perovskite (Ca,Sr)2InNbO6:Mn4+ red-emitting phosphors were prepared and further designed for the luminescence lifetime thermometers based on the temperature-dependent decay curves. At first, the crystal structure, morphology, and some luminescent properties (i.e., photoluminescence (PL) emission spectrum, concentration quenching mechanism, crystal field strength, chromaticity coordinate, color purity, quantum yield, thermal stability, and decay curve) of the Ca2InNbO6:Mn4+ and Sr2InNbO6:Mn4+ phosphors were systematically analyzed and compared. Afterward, it revealed that the PL properties of Ca2InNbO6:Mn4+ phosphors were excellent compared to Sr2InNbO6:Mn4+ phosphors owing to the stronger crystal field strength of Mn4+ ion. Most interestingly, the relative sensing sensitivities of the Ca2InNbO6:Mn4+ and Sr2InNbO6:Mn4+ phosphors were estimated as high as 3.30 % and 4.25 % K−1 with the low-temperature uncertainty of 0.11 and 0.09 K, respectively, indicating that the resultant novel double-perovskite (Ca,Sr)2InNbO6:Mn4+ phosphors could be proposed for luminescence lifetime thermometers with high sensing sensitivity.