摘要铝青铜合金具有许多优秀的性能，因而得到了飞快的发展，它代替了传统的材料被用以熔覆在其他各种金属的表面来满足各种特殊的条件。因此研究铝青铜的熔覆工艺显得非常有意义。

本文采用激光熔覆的方法，在45#钢上熔覆1mm厚的铝青铜。通过改变激光的功率和熔覆的速度来研究熔覆层的组织和力学性能变化（主要是硬度），进而研究分析工艺参数对铝青铜熔覆层的影响。

在实验中通过改变工艺参数得到数个试样，再借助金相显微镜、SEM扫描电镜、自动硬度仪等设备对熔覆层的组织和力学性能（主要是硬度）进行了分析。

结果表明：激光功率不变，随着熔覆速度的增加或者熔覆速度不变，随着激光功率减小，熔覆层受到的热影响会变小导致融化不完全，导致晶粒粗大。激光功率不变，随着熔覆速度的减小或者熔覆速度不变，随着激光功率的增大，由于合金元素的固溶强化，熔覆层的硬度会普遍变大。78232

毕业论文关键词：激光熔覆；铝青铜；组织物相；硬度

Abstract Aluminum bronze alloy has many excellent properties, which has been a rapid development, It’s cladded on the surface of various other metal to meet a variety of special conditions instead of some traditional materials。 So Aluminum bronze cladding process is very necessary。

In this paper, using the method of laser cladding to clad the aluminum bronze plate on the 45# steel。 By changing the laser power and speed of the cladding to study changes in microstructure and mechanical properties of the cladding layer (mainly hardness),  analysis and research impact of process parameters on the alloy。

In the experiment, changing the process parameters to obtain a number of samples, and then analysis and research the microstructure and mechanical properties (mainly hardness) by means of the cladding layer devices microscope like SEM scanning electron microscopy, automatic hardness tester 。

The results show that the laser power is constant, with an increase in the speed of the cladding or cladding speed constant, as the laser power is reduced, the heat-affected by the cladding layer becomes smaller resulting in incomplete melt, cause grain coarsening 。 Laser power is constant, with an reduce in the speed of the cladding or cladding speed is constant, with increase laser power, due to the strengthening of solid solution alloying elements, the hardness of the cladding layer will be generally bigger。

Keywords: Laser Cladding; Aluminum bronze; Organizational phase; Hardness

目录

第一章  绪论 1

1。1 课题的背景和意义 1

1。2 铝青铜合金的发展现状 2

1。2。1铝青铜合金的概述 2

1。2。2 铝青铜合金中合金元素对合金性能的影响 3

1。2。3 铝青铜合金国内、外研究现状 5

1。3 现代表面工程技术 6

1。3。1 概述 6

1。3。2 表面改性技术 6

1。4 激光表面改性技术 7

1。4。1 激光表面改性技术的含义及特点 7

1。4。2 激光熔覆 8

1。4。3 激光熔覆的原理及特点 8

第二章  实验材料、设备及方法 10

2。1 实验材料以及焊前预处理