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The addition of Si in a Cu–Ni– P –Pb (C19160) alloy has been fabricated by atmospheric smelting to approach high strength, high conductivity, and high-stress relaxation resistance. The addition of Si inhibited the coarsening and phase transition of Ni 5 P 4. The fine Ni 5 P 4 particles were dispersed in the matrix, which pinned dislocations and improved the studied alloy's strength and stress relaxation resistance. After homogenization at 900 °C for 4 h, cold rolled by 70 %, aging treatment at 450 °C for 1 h, cold rolled by 60 %, aging treatment at 400 °C for 45 min, cold rolled by 60 %, annealing treatment at 200 °C for 1 h, the C19160-0.1Si alloy shows an ultimate tensile strength of 705 MPa, electrical conductivity of 53.8%IACS, and a stress relaxation rate of 17.8 % after tested at 150 °C for 100 h. These findings have guiding significance for developing C19160 alloys with high strength, high conductivity, and high-stress relaxation resistance. • The changes of microstructure and properties during stress relaxation of C19160 alloy by adding Sn and Si were systematically studied. • The prepared C19160–Si alloy has high strength, high conductivity, and high-stress relaxation resistance. • The addition of Si effectively improves the high temperature stress relaxation resistance of the studied C19160 alloys. [ABSTRACT FROM AUTHOR]

Herein, fiber laser welding experiments are performed to evaluate the microstructure, mechanical properties, and corrosion behavior of dissimilar/similar joints between DP980 and QP980 steel. Results show that the fusion zone (FZ) of all joints consists of lath martensite with high microhardness (≈480 HV); the retained austenite content in the subcritical heat‐affected zone (HAZ) in the QP980 side of the dissimilar weld joint (WJ) is less than base metals (BMs). Lower hardness in the subcritical HAZ is found compared with BMs in all joints. The microstructure of softening zones is tempered martensite, and the reduction in hardness is about 8.5−10.8% of BMs, which has a great influence on the tensile fracture position of WJs. All joints fracture at softening zones with a typical feature of ductile fracture, and the joint efficiencies are above 96%. The electrochemical corrosion test reveals that the welded samples exhibit a higher corrosion rate compared with the BMs due to the increase in martensite content and area fraction of grain boundary. [ABSTRACT FROM AUTHOR]

A new type of intelligent lubrication functional material, Cu-5Sn/22vol%Cr 3 C 2 /16vol%Ti 3 SiC 2 composite, was fabricated by powder metallurgy. The mechanical and tribological properties of Cu-Sn/Cr 3 C 2 /Ti 3 SiC 2 composite were studied. Ti 3 SiC 2 , as a lubricating component, had a better reinforcing effect than graphite. Compared with Cu-Sn/Cr 3 C 2 /Gr composite, Cu-Sn/Cr 3 C 2 /Ti 3 SiC 2 composite exhibited a 97% increase in hardness and 144% increase in compressive strength, reaching 223 HV and 821 MPa, respectively. Moreover, Cu-Sn/Cr 3 C 2 /Ti 3 SiC 2 composite's wear rate was lower than those of Cu-Sn/Cr 3 C 2 /Gr composite under different loads. The enhancement was ascribed to the Ti 3 SiC 2 particles, which had a well-bonded interface with the matrix and induced a higher Orowan strengthening effect. The studied composites with enhanced mechanical and tribological properties have promising potential for application in bearings and mechanical transmission devices. • Cu-Sn/Cr 3 C 2 /Ti 3 SiC 2 composite was fabricated by mechanical alloying and vacuum hot-pressing sintering. • The mechanical and tribological properties of composites were improved by replacing graphite with Ti 3 SiC 2. • The formed mechanically mixed layers enhanced the wear resistance of Cu-Sn/Cr 3 C 2 /Ti 3 SiC 2 composites. [ABSTRACT FROM AUTHOR]

The tin bronze- x Cr 3 C 2 -graphite composites (x = 5, 10, 15, and 20 wt%) were fabricated by mechanical alloying and spark plasma sintering. Fine-scale uniform distribution of composites was achieved. The Cr 3 C 2 particles enhanced the mechanical properties and wear resistance of copper-based composites. The as-sintered tin bronze-20Cr 3 C 2 -graphite showed a hardness of 109 HV, a compressive strength of 333 MPa, and a yield strength of 219 MPa. In addition, the wear rate of as-sintered tin bronze-20Cr 3 C 2 -graphite was maintained in the order of 10−5 at 30 N, 50 N, and 70 N. The wear mechanism of the studied composites varied from surface fatigue and adhesion wear to abrasive wear with the increase of Cr 3 C 2 content during dry sliding. These findings provide a new method for developing copper-based composites with enhanced mechanical properties and wear resistance. • The tin bronze-Cr 3 C 2 -graphite composites were fabricated by powder metallurgy. • The Cr 3 C 2 particles enhanced the mechanical properties and wear resistance of copper-based composites. • The wear mechanism of the studied composites varied with the increase of Cr 3 C 2 content. [ABSTRACT FROM AUTHOR]