Effect of Y on interface characteristics and mechanical properties of brazed diamond with Ni Cr filler alloy

Diamonds brazing with a novel Cu35Ni35Cr10Fe10Sn10 high‐entropy alloy filler

“…The size of the diamond particles was about 35 ). The heating and cooling rates were kept con-stant at 10 • C/min.…”

“…Meanwhile, it is noted that the fracture strength of 4009.4 MPa at the preferred brazing temperature of 1000 • C was not so much lower that of the virgin diamond, and was indeed almost 2.5 times than that using the NiCr-based filler, 1852.7 MPa, in our previous report. 35 The fracture strength is mainly related to the graphitization degree of diamond: the more severe the graphitization, the easier the diamond breaks under pressure. Graphitization of diamond after high-temperature brazing is first related to the brazing temperature, and (B) Figure 11 shows the friction coefficient versus time curves and the weight loss of ceramic tiles for brazed diamond joints.…”

“…The strong carbide-forming element, Cr, contributed to achieving high bonding strength through interfacial metallurgical reactions with low thermal damage. The low thermal damage was first due to the low brazing temperature, second due to the reduced Ni content in the HEA filler compared to that in conventional NiCr-based fillers and therefore the diminished effect from catalytic reaction of Ni, 11,35 and third due to infinite solid solution between Cu and Ni, which weakened the catalytic reaction of Ni and the graphitization of diamond, according to Refs., 20,21 where the influence of Cu on the NiCr-based filler was studied.…”

“…A high content of Sn would make the alloy brittle. Therefore, the contents of Cr, Fe, and Sn were reduced by half, and eventually the HEA filler composition was set to Cu 35 , where c i is the mole fraction of the element i, n is the number of elements, and R is the gas constant (8.3145 J/(mol K)). The calculated ΔS mix of the Cu 35 Ni 35 Cr 10 Fe 10 Sn 10 HEA is 1.42R, which strictly speaking would define it as the medium-entropy alloy (MEA), with R ≤ Δ𝑆 mix ≤ 1.5𝑅.…”

Effect of Y on Arc Breaking Behavior of Platinum–Iridium Alloy Contact Materials at Different Voltages

“…For Ti-48Al (at.%) alloys, the microhardness of the alloys increased with the increasing Y content [20]. When brazing a diamond with the Ni-Cr alloy filler, the introduction of Y could reduce the possibility of cracking, refine the grain size, reduce the thickness, and effectively release the thermal stresses of the joint in the carbonized layer [21]. Our team found that the addition of Y to the Pt-24Ir alloy could effectively refine the microstructure of the alloy, which improved the hardness and strength of the alloy, and, at the same time, had more excellent resistance to arc erosion [22].…”