WC颗粒增强铜基合金覆层用钎料的研究

研制了一种新型钢用WC颗粒增强铜基合金覆层用的CuMnNiCr多元铜基钎料,对该钎料的熔化特性、钎料组织、钎焊工艺及力学性能进行了研究,并通过优化的钎焊表面合金化工艺,在普通铸钢件表层制得了WC颗粒增强铜基合金耐磨覆层.研究结果表明,与普通的CuZnNi、CuMnNi合金钎料及NiCrBSi高温自熔合金钎料比较,CuMnNiCr多元合金钎料由于多种强化机制而具有优良的综合力学性能.此外,该钎料还具有优异的钎焊冶金特性、致密的冶金结合界面以及较高的界面结合强度.使用该钎料制备的复合覆层具有良好的综合性能.SEM,EDS及XRD分析表明:该复合覆层与钢母体结合牢固;覆层内合金基体与WC颗粒形成了冶金结合,WC的体积分数可达54%,复合覆层组织由α-Cu固溶体基体、α-Cr与MnNi弥散硬化相及WC硬质相组成.磨损实验证明,该覆层的耐磨性远优于30MnSiTi马氏体低合金钢.

STUDY OF BRAZING ALLOY USED IN BRAZING COMPOSITE ALLOY CLADDING REINFORCED WITH HARD PARTICLES

ABSTRACT A new type of brazing alloy used in brazing composite alloy cladding reinforced with hard particles on steel substrate was developed in this paper. Using the brazing alloy, stable composite alloy cladding on surface of common steel castings was made by optimum brazed hardfacing process. The composite alloy cladding is superior to other claddings obviously in design and regulation of cladding composition, microstructure and performance as well as thickness (maximum up to 30mm) according to practical demands. Besides, it is possessed of good combination property. SEM observation, energy spectrum and XRD analysis have shown that the composite alloy cladding is in strong combination with steel parent metal, and metallurgical bonding is formed between copper brazing alloy matrix and WC grains in the cladding wherein volume fraction of granular WC phase can be up to 54%. The composite alloy was composed of copper alloy solid solution as base-alloy, Cr-phase and MnNi type of compound dispersion phases as well as WC hard phase. WC particles with different grain sizes and volume fractions were close and well distributed in dispersion strengthened copper alloy. Impingement erosion wear tests have proved that the composite alloy is far superior to 30MnSiTi low-alloy steel in wear resistance.