Starting elements comprising Se, Te and Cd with 99.999% purity were employed in this study and a silica cylindrical vessel, measuring 1.0 cm in diameter and 20.0 cm in length, was loaded with predetermined mass percentages of these elements. A low pressure of 10⁻⁴ Torr was then blown down the tube and the tube thermally sealed. It was fitted into an electric oven Heraeus (type Ro7115) programmable cylinder heater. Se₉₀Te₁₀ and (Se₉₀Te₁₀)₉₅Cd₅ at.% were furnace at 600°C and 50°C, respectively, for 40 h. Silica tubes were agitated at three-hour intervals throughout the heating process to ensure uniform mixture composition. The tubes were quenched in a container containing crushed ice and water after heating. The mixture was then collected and ground into small grains using a hand mortar.

Using a CuKα of λ = 0.154 nm, the Philips 1710 type was used to measure the samples’ degree of crystallinity. The samples were examined using a “Philips Paradigm” XL30 electron scanning microscope (SEM).

The compressive strength of the laboratory-prepared specimens was quantitatively determined to characterize their mechanical performance under axial loading; this critical assessment was conducted in strict accordance with the standardized test method delineated in ASTM C109/C109M, which governs the compression testing of hydraulic cement mortars. The experimental procedure was executed utilizing a (Matest C088-10N Concrete compression machine), a precision instrument configured with a 10 kN capacity load cell to ensure accurate force measurement; To guarantee quasi-static loading conditions and mitigate the influence of strain rate effects, a constant crosshead displacement rate was meticulously maintained at 1.0 mm per minute throughout the duration of each test until specimen failure was achieved.

DSC was utilized to assess the behavior of crystallization under non-isothermal conditions using the Shimadzu TA-50 instrument (Kyoto, Japan). An amount of about 5 mg of a powdered sample was loaded into the benchmark aluminum pan and dried in a nitrogen-free environment; heating rates of 5, 10, 15 and 25 K/min were employed to obtain non-isothermal DSC curves. T_g, T_c, and T_p are the additional result values derived from those curves.

Fig. 1 displays Se₉₀Te₁₀ and (Se₉₀Te₁₀)₉₅Cd₅ the XRD curves which illustrat the samples’ amorphous character. A hump in the baseline usually indicates the presence of an amorphous material in the sample. This feature, which appears at higher 2θ angles, is characteristic of medium-range order in amorphous chalcogenide glasses, reflecting correlations between atomic clusters that extend beyond the nearest-neighbor distances. Similar observations have been reported in Se–Te and related chalcogenide glasses, where the first broad hump corresponds to short-range order (nearest-neighbor distances) and the second broader hump reflects intermediate-range structural organization [10].

The nature was becoming apparent through lone-pair computations with the help of L = V − <r> [11,12], where r   =   αN x + βN y + γN z α + β + γ and V is a valence electrons, α, β, and γ are the concentrations of (Se₉₀Te₁₀) and (Se₉₀Te₁₀)₉₅Cd₅, respectively. The lone pairs were calculated 4, 3.7 for (Se₉₀Te₁₀) and (Se₉₀Te₁₀)₉₅Cd₅, respectively [13]. The calculated bond stretch N_a = <r>/2 equals 1.05, bond bending N_b = 2 <r> − 3 equals 1.2, and the number of concentrations N_c = N_a + N_b equals 2.25 for (Se₉₀Te₁₀)₉₅Cd₅. It is evident that the syntheses under study are amorphous and it was confirmed by the appearance of bumps in patterns of the amorphous material. Thus, the SEM micrograph Fig. 2, of glassy fracture lacking any layer structure confirmed the results [14].

The mechanical behavior of the (Se₉₀Te₁₀)₉₅Cd₅ alloy aligns with the typical characteristics observed in amorphous chalcogenide glasses, demonstrating acceptable intrinsic strength concurrent with restricted ductility; A measure of the failure load of 0.032 kN, presumably obtained via micro-indentation or small-scale compression testing, reflects substantial mechanical integrity within this material class: Such as value is indicative of robust resistance to deformation, consistent with the brittle fracture mode and the absence of pronounced plastic flow characteristic of vitreous alloys. Furthermore, the incorporation of cadmium into the (selenium-tellurium matrix) is designed to engineer its structural attributes, ostensibly improving thermal stability and mechanical robustness as corroborated by the aforementioned mechanical data.

The (Se₉₀Te₁₀)₉₅Cd₅ alloy exhibits a high small-scale failure load (0.032 kN), indicating enhanced resistance to deformation compared with undoped Se and is consistent with reported Se–Te binaries. The presence of cadmium and tellurium increases microhardness and thermal/structural stability while retaining the brittle fracture mode typical of amorphous chalcogenide glasses, making this composition attractive where mechanical robustness and glassy optical properties must be combined:Pure amorphous Se is generally softer and more easily plastically deformed at the microscale than Se–Te alloys; showing lower hardness and lower resistance to indentation. Se → Te substitution typically increases hardness and resistance to crystallization [15]. Se–Te binary glasses exhibit enhanced mechanical properties compared with pure Se. Recent nanoindentation studies have reported a significant increase in hardness and elastic modulus with increasing Te content, confirming that Te incorporation strengthens the network structure and improves mechanical stability [16].

A DSC scan of the multi-component chalcogenide glasses (Se₉₀Te₁₀)₉₅Cd₅ at heating rates of 5, 10, 15 and 25 K/min is displayed in Fig. 3 whereas a variation in temperature under consideration is given, the DSC thermogram distinctly reports the presence of two different phenomena, namely endothermic and exothermic peaks. Analytically, DSC thermograms are divided into two segments. The exothermic segment of the DSC curve shows the crystallization process, and the first part associated with glass transition which is depicted by an endothermic reaction. Temperature points where endothermic and exothermic peaks, corresponding to dual linear sections defining DSC trace transition elbows, intersect are designated as Glass transition temperature (T_g) and onset crystallization temperature (T_c) terminology. Peak crystallization temperature (T_p) represents the maximum temperature of exothermic peak occurrence during crystallization processes. Table 1 indicates that an increase the peak crystallization temperature (T_p) which corresponds to the exothermic peak in the crystallization region, shows that T_g, T_c, T_p, and (T_c − T_g) increase with heating rate. The same observation was recorded by Mehta et al. [17] in terms of adding certain metallic additives (Ag, Cd and Sb) to the Se₈₀Te₂₀ alloy glass, and similar effects have also been observed in other chalcogenide systems [18,19].

The small deviation appearing at the initial part of the DSC curves for the higher heating rates (15 and 25 K/min) can be attributed to thermal response delay and baseline instability inherent to fast heating scans. At elevated heating rates: the temperature difference among the sample and the reference increases, leading to a slight distortion in the heat flow signal before thermal equilibrium is established; This effect is absent or significantly reduced at lower heating rates (5 and 10 K/min), confirming its instrumental origin rather than a physical transition, the dip observed in all DSC curves after crossing approximately 500 K is associated with an endothermic structural relaxation process occurring in the vicinity of the glass transition temperature (T_g). The relaxation process within the amorphous phase has several features: the reason is of twofold: (1) it is non-exponential in its time dependence; (2) it is non-linear in its structural state dependence. This feature arises from atomic rearrangement and the release of frozen-in stresses within the amorphous chalcogenide network as the material approaches the supercooled liquid region. Similar relaxation endotherms near T_g have been widely reported for chalcogenide glasses and are considered a characteristic signature of glassy systems, rather than evidence of crystallization or a first-order phase transition [20,21].

The glass transition zone of the materials has been verified and the thermal stability of the glassy alloy may be put as the change of glass transition temperature T_g against heating rates [22]. The T_g heating rate dependency can be discussed in three respects: “Kissinger formulation”, Lasocka and Augis and Bennett models [23]. To begin with, it can be stated that “Kissinger formulation”: is one of the most widely used methods for non-isothermal stage transition researches in thermal DSC curves study [24]: This arrangement is meant to discuss the kinetics of transformation in an isothermal state, as well as to give a generalization of the formal Avrami phenomenon equations to be applied in continuous (or non-isothermal) conditions of crystallization. Kissinger notes that activation energy value of E_c should be calculated according to the following formula [9]: (1) ln α / T p 2 = − E c / RT p + const where α ; Heating rate used in DSC scans, R is the constant of generic gas (R = 8.314 J K⁻¹ mol⁻¹). Soliman was applied Kissinger’s theoretical ideas to calculate the energy value by replacing a peak temperature with glass temperature and an activation energy with the energy value thus this results in the glass transition kinetics equation, Eq. (2) as follows [9]:

E_g: energy activation values for the glass transition. Fig. 4 and Fig. 5 refer to ln α / T p 2 versus 1000/T_p for (Se₉₀Te₁₀)₉₅Cd₅ glasses and ln α / T g 2 versus 1000/T_g for (Se₉₀Te₁₀)₉₅Cd₅, respectively, The E_c and E_g values were deduced from Eqs. (1) and (2) in Table 2.

Next, Lasocka proposed an empirical relationship in the following form [25]:

The third estimation by Augis and Bennett [23] is referred to as “a streamlined version of Kissinger’s technique”, as detailed [25]:

In Fig. 6, we can observe a linear relationship amidst ln(α) and T_g for (Se₉₀Te₁₀)₉₅Cd₅ glasses, A and B act as constants determining the composition of the glass. A and B values were thoroughly analyzed in Table 2. Values obtained from A and B are considered perfect for all samples for both glass transition temperatures [26,27].

Fig. 7 and Fig. 8 display the relationship between ln(α/T_g) and 1000/T_g for (Se₉₀Te₁₀)₉₅Cd₅ glass and ln(α/T_p) and 1000/T_p for (Se₉₀Te₁₀)₉₅Cd₅ glass, respectively. The values of E_g and E_c could be found in Table 2.