采用预制涂层激光合金化法 ,在镍基高温合金Inconel 6 2 5表面预置WC -TiC粉末涂料 ,在增碳、锆条件下可获得成形好、无裂纹、与基材形成冶金结合的合金化层。合金化层组织特点是在γ -Ni枝晶内和枝晶间均匀分布大量从液态析出的复合碳化物。电子探针微区分析表明 ,在γ -Ni枝晶内析出富Ti、Nb、Zr、W、Mo的颗粒状复合碳化物 ,颗粒尺寸 1～ 2 μm ,颗粒数达 10 4个 /mm2 量级 ;在γ -Ni枝晶间析出富W、Mo、Cr的形态复杂的条、块状复合碳化物。合金化层显微硬度约为HV0 .2 4 0 0 ,比Inconel 6 2 5合金硬度HV0 .2 2 5 0提高了 6 0 %。环块磨损试验发现 ,上试样为GCr15标准环时 ,激光合金化层耐磨性是Inconel6 2 5合金的 4 .1倍 ,摩擦系数降低 16 % ,耐磨性与钢表层氮化处理试样相当。上试样为渗碳淬火钢环时 ,激光合金化层耐磨性是钢氮化处理试块的 5 .7倍。研究表明 ,镍基高温合金Inconel 6 2 5表面激光合金化制备原位自生复合碳化物颗粒为增强相的激光合金化层具有很好的工艺重现性。

laser alloying by preplaced WC-TiC layer on the surface of Ni-base superalloy Inconel 625 has been investigated in this paper. The experimental results indicated that on the condition of carburetion the alloyed layers with preplaced WC-TiC layers were metallurgically bonded to the substrate with fine shape and free of pores & cracks was performed. One of the microstrutural characteristics of alloyed layers was the homogeneous distribution of a large quantity of in-situ complex carbides particles precipitated directly from liquid solutions on the γ-Ni matrix. The electron probe microanalysis indicated that the size of these particles were in the range of one to two microns, and their number was amount in a order of 104/mm2. the particles which distributed on γ-Ni matrix were rich in Ti,Nb,Zr, W and the Mo elements. The precipitated intergranular phases were compound carbides with complex shape and rich in W, Mo and Cr elements .The microhardness of alloyed layers was about HV_ 0.2400 which was 60% higher than that of the Inconel 625(HV0. 2250) . The ring and block wear test results showed that the friction coefficient between the alloyed layers and the upper GCr15 standard rings was 16 % lower than that between the Inconel 625 and the rings. the wear resistance of the laser alloyed layers was 4. 1 higher than substrate Inconel 625 and as same as nitrogen treatment steels. The wear resistance of the laser alloyed layers was 5. 7 higher than the nitrogen treatment steels if the upper sample is carburizing and quenching steel rings. The results showed that laser alloying composite layers reinforced by in - situ complex carbides on Inconel 625 substrate had high technique repetition.