A kind of method of powder sintering preparation Al-SN base bearing alloy

Abstract

The invention discloses a method for preparing an Al-Sn-based bearing alloy by powder sintering. Raw powders such as Al and Sn and powders such as pretreated Si are mixed according to a certain weight percentage, and then processed by ball milling to obtain Al-Sn-based bearing alloys. Si nanocrystalline alloy powder, the above alloy powder is prepared by "pre-cold pressing + sintering + cold rolling + recrystallization annealing" process to prepare a fully dense Al-Sn-based bearing alloy. The Al-Sn-based bearing alloy prepared by the invention has a dual-scale structure, that is, micron coarse-grained Al phases are distributed in an ultra-fine-grained Al matrix, and the dual-scale structure has the controllability of strength and plasticity. The invention solves the key problems such as difficulty in sintering and non-densification produced during the industrial application of powder sintered Al-Sn-based bearing alloys and bearing bush strips, and easily realizes industrial production.

Description

technical field [0001] The invention relates to a preparation method of an Al-Sn-based bearing bush alloy, in particular to a method for preparing an Al-Sn-based bearing bush alloy by powder sintering. Background technique [0002] With the rapid development of transportation equipment such as high-speed railways, light rails, subways and ships, as well as the trend of high compression ratio, compact design and weight reduction of engines, not only the application range of bearing alloys (such as Cu-based, Al-based, etc.) has been significantly expanded, It also puts forward higher requirements for its bearing capacity and tribological properties. Moreover, the European Union has banned the use of lead in engine bearings for light vehicles since July 1, 2011. This regulation has brought extensive changes to automotive bearing alloys and bearing coatings. Although there are no similar regulations for heavy-duty engines, it is only a matter of time. Therefore, it is an urgen...

AI Technical Summary

Problems solved by technology

However, there are two main problems in the Al-Sn alloy obtained by casting: (1) the strength of the alloy (HV30~50) is low, and it is difficult to meet the current demand for high strength of the bearing bush; (2) it is easy to serious problems such as gravity segregation

However, for Al-Sn-based bearing alloys, cast aluminum-tin-based ingots are mainly used in the industry, and then compounded with steel backs to form bearing strips. The easy oxidation of the powder leads to poor sintering performance between powder and powder, powder and steel back, and poor bonding strength, and there are four problems produced during the industrial application of Al-Sn-based bearing alloys prepared by mechanical alloying. Insufficient technology: (1) nanocrystalline powder has high hardness and poor fluidity, and it is difficult to combine with steel back rolling; (2) because Al powder particles are easy to oxidize, it is difficult to use hot rolling method, and at the same time, it is difficult to obtain cold rolling with steel back High bonding strength; (3) The surface of Al powder particles is easy to absorb water, and more air bubbles are generated during the composite rolling process, which seriously affects the bonding strength between the alloy layer and the steel back; (4) If the cold rolling Al powder and steel back are co-solidified and sintered at high temperature (above 500°C), and it is easy to form Al-Fe hard and brittle phase at the interface

The above problems, on the one hand, show that powder sintering of Al-based alloys faces many challenges, and the aluminum alloys commonly used in industry are mostly prepared by casting methods;

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