摘 要

非晶合金是一类异于传统金属的材料，其硬度，强度高，韧性塑性好，却因制备方法较为复杂繁琐，导致块体状非晶合金体积都很小，目前已有众多科研学者利用固相焊，熔化焊，钎焊等方式将小块状的非晶合金进行焊接拼合，但不同的焊接方法对焊后材料的影响也不尽相同。例如：随着搅拌摩擦焊搅拌速度的增加，Ti-Zr基非晶接头由解理断裂转变为脆性断裂，接头强度降低；随着激光焊接焊接速度的降低，Ti-Zr基非晶接头中开始出现晶体相，接头断面形貌由均匀的脉状形貌转变为层状形貌，接头强度也随之降低。

基于此，本文则利用超声波辅助Zn-3Al钎料对Zr基非晶合金进行钎焊，采用16s，32s，64s，96s为时间变量，400℃，415℃，430℃为温度变量，并对不同变量下的材料进行硬度和剪切强度的测试，并用显微镜观察其断面形貌及截面形貌。通过一系列实验，得到以下结论：

（1）Zr基能在超声波辅助下焊接得力于超声波的空化作用，超声波作用时间越长，对母材表面氧化膜破坏作用越明显，使钎料直接与新鲜金属反应，钎料对母材的润湿越好。400℃时，反应层厚度从几乎为0变为368.42μm，生成的金属间化合物层厚度越厚，焊接接头质量越好。

（2）焊接接头的质量随着超声作用时间和温度升高而升高，强度方面，430℃下96s焊接区的金属间化合物最高硬度为640MPa，430℃下64s焊接区的金属间化合物最高硬度为580MPa，而413℃下96s的焊接区金属间化合物最高硬度为560MPa；剪切强度方面，400℃下接头剪切强度从16.12MPa上升到64.97MPa，430℃下接头剪切强度由22.35MPa上升到97.63MPa。

（3）超声波辅助Zn-3Al对Zr基进行的焊接，在剪切外力作用下，其破坏形式为解离断裂，为脆性断裂中的一种，断裂界面呈现河流花样状。

关键词：Zr基非晶合金，超声波辅助钎焊，断裂形貌

Abstract

Amorphous alloy is a kind of material different from the traditional metal, its hardness, high strength, toughness and plasticity, but because of the preparation method is more complex and cumbersome, resulting in block-like amorphous alloy volume is very small, there are many researchers use Solid-phase welding, melting welding, brazing, etc. will be small pieces of amorphous alloy welding together, but different welding methods after welding the impact of different materials. For example, with the increase of the stirring speed of the friction stir welding, the Ti-Zr-based amorphous joint is changed from cleavage fracture to brittle fracture, and the strength of the joint is reduced. With the decrease of the welding speed of the laser welding, the Ti-Zr-based amorphous joint starts The crystal phase of the joint is changed from a uniform pulse morphology to a layered morphology, and the joint strength is reduced. Based on this, the Zr-based amorphous alloy was brazed with ultrasonic-assisted Zn-3Al brazing filler metal. The temperature was 16s, 32s, 64s and 96s as the time variable, 400 ℃, 415 ℃ and 430 ℃, The hardness and shear strength of the material were tested and the cross-sectional morphology and cross-sectional morphology were observed with a microscope. Through a series of experiments, the following conclusions are obtained:

(1) Zr-based in the ultrasonic-assisted welding of the cavitation of the ultrasonic effect, the longer the role of ultrasonic waves on the base metal oxide film damage the more obvious, so that the direct contact with the fresh metal solder to improve the welding of the base metal The better the wetting, the higher the strength of the intermetallic compound layer, the better the quality of the welded joint.

(2) The quality of the welded joint increases with the time and temperature of the ultrasonic action, and the maximum hardness of the intermetallic compound in the 96s solder zone at 430 ℃ is 640MPa, and the intermetallic compound at 64s in 430 ℃ is the highest The hardness is 580MPa, and the maximum hardness of the intermetallic compound is 96MPa at 96s in 415 ℃. The shear strength of the joint increases from 16.12MPa to 64.97MPa at 400 ℃, and the shear strength is from 22.35MPa to 97.63MPa.

(3) Ultrasonic assisted Zn-3Al for Zr-based welding, under the action of shear external force, the destruction of the form of dissociation fracture, is a brittle fracture, fracture interface showed river pattern.

Key Words: Zr-based bulk metallic glasses, Ultrasonic-assisted brazing, Fracture morphology

目录

第1章 绪论 1

1.1项目研究背景及意义 1

1.2国内外研究现状 2

1.2.1 Zr基优异性能简介 2

1.2.2常用的焊接方法 3

1.2.3超声波辅助钎焊的原理 5

1.2.4不同焊接方法下的断裂形式和破坏机制 6

1.3本文的研究内容与技术方案 7

1.3.1研究内容及目标 7

1.3.2研究技术方案 7

第2章 实验材料和研究方法 8

2.1实验材料 8

2.2实验设备与研究方法 8

2.3样品的测试与断裂显微形貌观测 10

第3章 结果与分析 12

3.1接头形貌整体概述 12

3.2工艺参数对焊接质量的影响 14

3.2.1硬度拟合曲线 14

3.2.2 剪切强度曲线 16

3.3焊接接头的探究 18

3.3.1 Zr基母材表面氧化膜的破碎 18

3.3.2失效形式与断裂部位 19

结论 22

参考文献 23

致谢 26

第1章 绪论

1.1项目研究背景及意义

1960年，W. Klement (Jr.), Willens 和 Duwez等人^[1]通过急速冷却（冷速速率106K/s）制得Au₇₅Si₂₅非晶态合金，这是最早被报道的非晶态合金。非晶合金是一类性能奇特的金属材料，又被称为金属玻璃（BMG），这类金属有着长程无序，短程有序的结构特点，因其没有晶粒，晶界的存在，因此在物理，化学，光学，力学等方面有着不同于传统金属材料的优异性能，非晶合金的强度高，耐腐蚀性能好，韧性好，同时一部分非晶合金还兼具优异的磁学性能^[2,3]。

近年来，非晶合金受到人们的广泛关注，在材料学领域中成为一个科研热点。其中，由于Zr基非晶合金具有很强的玻璃形成能力和较宽的过冷液相区，能够较容易地制备出尺寸较大的块体非晶合金 ^[3]。同时，Zr基非晶合金同样具备上述的优异性能，是目前研究得最多的非晶合金系之一^[4]。而且根据近些年的文献资料报道，大量的研发工作表明，块体状的非晶合金材料在航空航天，汽车，电子通讯等领域有着光明的发展前景^[3]。