Fracture and wear of the Sn11Sb5.5Cu Babbitt after equal-channel angular pressing

Abstract

A computer simulation and experimental study of the Sn11Sb5.5Cu Babbitt rods deformation by equal-channel angular pressing (ECAP) was carried out. The material was studied in two structural states. The first one (state I) produced by conventional crystallization during casting is characterized by large particles of the intermetallic β-and η-phases. In the second state (state II) produced by fast crystallization, the material contained small particles. ECAP processing was performed in a die with vertical and horizontal channels intersecting at a right angle, with pressure imposed by a punch located in the vertical channel of the die. On the basis of the computer simulation of the process by means of the DEFORM-2D software, the deformation speed providing the lowest damage of the workpieces was selected. The wear was determined by measuring the weight loss of the sample due to friction. The dependence of the Babbit wear in state I has two clearly distinguished stages of running-in and steady-state wear. The wear of the samples in state II shows that the produced uniform distribution of intermetallic particles in the matrix phase leads to the absence of the running-in stage during wear. Severe plastic deformation (SPD) processing by ECAP leads to the dispersion of intermetallic phases particles and the weakening of the adhesive bond between the particles and the matrix. In state I, the refinement of large intermetallic particles causes a decline in wear. In state II, after ECAP, the adhesion to the matrix weakens, and the softening of intermetallic particles occurs, which causes an increase in wear. Thus, SPD processing is not an efficient method for improving the tribological characteristics of the Sn11Sb5.5Cu Babbitt. In this case, the methods for producing a fine-grained structure, based on the variation of the crystallization rate during casting, are more effective and less costly.

Study on fatigue strength of SnSb11Cu6 babbitt-steel bimetal sliding bearing material prepared by MIG brazing

“…Preparation methods of babbitt-steel bimetal materials include centrifugal casting [5,6], arc spraying [7], plasma-arc powder deposition [8], laser cladding deposition [9], TIG arc brazing [10], MIG arc brazing [11], etc., and each preparation method has its advantages. Different characteristics, such as the contact-impact [1], the mechanical and tribological properties [12], the fracture and wear [13] and the creep characteristics [14] have been studied by many researchers. Moreover, babbitt alloys have a variety of failure modes.…”