A Study On The Microstructure Of Spray-deposited Magnesium Alloys During The Thermal Compression Process

Magnesium alloy is the lightest structural metal in engineering applications, with ahigh specific strength and good damping. It meets the lightweight exhibited and energy-saving of products in aerospace, automotive, military and other industries. Magnesiumalloy prepared with spray deposition technique is characteristics of fine grains, high-alloying, high thermal stability and excellent mechanical properties. But magnesium alloyis of hexagonal structure, with poor plastic forming ability and easy to form a strong (0002)basal texture, limited its application.Previous studies have shown that Ca and Nd elements, for example, can significantlyreduce the intensity of the texture. The influence of compound addition of Ca and Nd onthe texture of alloys has very little studies. Base on it, this thesis adopts the spraydeposition Mg-9Al-3Zn-6Ca-1Mn-1Nd alloy extrusion billet, make use of compressiondeformation of different processes, studying the deformation process on the evolution ofmicrostructure and texture of thermal compression and learn the effects of process on thetexture. The results of studies show that:(1) The grain size of spray spray-deposition Mg alloys extrusion billet Mg is about3μm. There are a number of (Ca,Nd)Al2phases with the size of300nm in the matrix. Thelamellar structure is Mg-Nd-Zn series LPSO structure, structure type is24R. A strong(0002) texture has formed in the alloy.(2) At a temperature of250℃and a deformation rate of1s-1, with the deformationprocess, both prismatic and pyramidal texture are formed significantly and the basaltexture is weakened simultaneously. When the deformation degree is0.6, a complextexture with basal texture, prismatic and pyramidal texture has been formed in the alloy.(3) The alloy deformation texture is sensitive to the deformation rate and deformationtemperature. The high deformation temperature and deformation rate are helpful to the alloy achieve texture “randomization”. At a temperature of350℃and a deformation rateof1s-1, the lever of texture “randomization” of alloy is higher.