Assignment first：固态焊接的简介
焊接是将两个或两个以上的零件连接起来以确保它们完全结合在一起的过程。焊接的目的是确保两个不同或相似的材料连接。传统焊接方法存在的问题是LFW等新型焊接方法产生的原因。焊接通常是通过热和压力来实现的。根据使用的基材的状态，焊接的形式通常是不同的，熔焊和固态焊是基于焊接状态特征的几种焊接形式
Assignment first：固态焊接的简介
固态焊接不同于熔焊过程，焊接操作是在界面层面进行连接或融合。在这里，两个或多个表面被带入液体或熔融状态，然后关节被创建(Vairis & Frost, 1998)。通常，在固态焊接中比较流行的焊接种类是扩散焊接，其次是摩擦焊接和超声波焊接。扩散焊接是在高温高压下实现聚结的过程。在扩散焊接的情况下，通常认为表面的变形是最小的，因此在航空航天应用中，它得到了广泛的应用(Zink, 2001)。在航空航天工业中，需要焊接的不同材料通常都采用这种焊接方式(Abel et al, 2015;Tavares, et al, 2013)。这些是航空航天工业中使用的传统方法，它们本身存在一些问题和缺陷(如下图所示)，这也是寻找新焊接技术并对其进行分析和评估的原因之一。
Assignment first：固态焊接的简介
Welding is the process where two or more pieces are joined in order to ensure that they are completely coalesced. The purpose of welding is to ensure that two dissimilar or similar materials are joined. The creation of these monolithic structures is usually tested for strength and assessed for durability as well. The issues in conventional welding methods are the reasoning behind why newer welding methods such as LFW came into existence. Welding is usually achieved by means of heat and pressure. The forms of welding will usually be different based on the state of base material that is used. Liquid state welding which is called as fusion welding and solid state welding are some of the types based on welding state characteristics.
Assignment first：固态焊接的简介
Solid state welding is different from the fusion welding process in that the welding operation will take place as a joining or fusion happening at the interface level. Here two or more surfaces are brought into a liquid or molten state and then the joint is created (Vairis & Frost, 1998). Usually, the welding category that is more popular in the case of solid state welding is the diffusion welding, and secondly friction welding and ultrasonic welding is done. Diffusion welding is a process in which the coalescence is usually achieved at elevated temperature with high pressures. In the case of diffusion welding it is often established that deformation at surface level is minimal and hence in the context of aerospace applications it finds much use (Zink, 2001). Often dissimilar materials that need to be welded in the case of the aerospace industry is usually done with this kind of weld (Abel et al, 2015; Tavares, et al, 2013). These are conventional methods used in the aerospace industry that lend itself some issue and defects (as given in the below image)which is one of the reason for the search of newer welding techniques and analysis and assessments of the same.
