**5. Conclusions and Prospects**

The principle and process of impact welding are described, and the difference between laser impact welding and another impact welding is illustrated above in this work. It also describes the research progress in recent years, and summarizes its application prospects, the difficulties in industrial applications and the mechanism problems currently to be studied as follows:


**Author Contributions:** Conceptualization, H.W.; Investigation, K.W., H.W., H.Z. and A.X.; Writing—Original Draft Preparation, K.W., H.Z. and H.W.; Writing—Review & Editing, K.W., H.W. and W.Z. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by Beijing Municipal Science and Technology (Z201100004520011), National Natural Science Foundation of China (61409220124), Fundamental Research Funds for the Central Universities (06500107).

**Acknowledgments:** The authors thank all the lab members for the discussion and help. Particularly, the authors appreciate the excellent research work from the researchers included in this review.

**Conflicts of Interest:** The authors declare no conflict of interest.
