Preparation And Studies On The Properties Of Soluble Magnesium Alloys

The world is rich in shale gas resources.Fracturing is the most effective measure to increase the output of single wells in low permeability reservoirs.Fracturing tool?fracturing balls and bridge plug?play a crucial role in the whole fracturing process.The soluble magnesium alloy is a new attempt of fracturing tool.The soluble magnesium alloy with excellent properties was prepared by casting.The microstructure of soluble magnesium alloy was observed using OM and SEM.The phase composition of soluble magnesium alloy was analyzed using XRD and EDS.The effects of solid solution and aging treatment on the microstructure and properties of soluble magnesium alloy were studied.Dissolution behaviors of as-cast and heat treated State soluble magnesium alloy were analyzed by dissolving weight loss method and electrochemical test.Finally,the dissolution mechanisms of soluble magnesium alloy were discussed.The effects of aluminum elements content on the microstructure and properties of as-cast soluble magnesium alloy were studied.The results revealed that the microstructure of soluble magnesium alloy comprised the following two phases:?-Mg and?-Mg₁₇Al₁₂.?-Mg₁₇Al₁₂ was increased with an increase in aluminum content and was continuously distributed in the?-Mg grain boundary.The soluble magnesium alloy could dissolve in the 3wt.%KCl solution,in addition,the dissolution rate increased with an increase in aluminum content until the dissolution rate reached7.42 mg·h^-1·cm^-2.The dissolution rate is proportional to the number of?-Mg₁₇Al₁₂.At the higher temperature,the solubility of the soluble magnesium alloy is better.The compressive strength of the soluble magnesium alloy could reach 430 MPa and the material broke when the deformation reached3.0%.The effects of lanthanum elements content on the microstructure and properties of as-cast soluble magnesium alloy were studied.The results revealed that the microstructure of soluble magnesium alloy with lanthanum elements addition comprised the following two phases:?-Mg and?-Mg₁₇Al₁₂ and Al₁₁La₃.?-Mg₁₇Al₁₂ of soluble magnesium alloy decreased significantly with lanthanum elements addition.?-Mg₁₇Al₁₂ distributed in the grain boundary with a lump and strip.Thus it effected the properties of the soluble magnesium alloy.The dissolution rate decreased with an increase in lanthanum content.In addition,the compressive strength and plasticity increased with an increase in lanthanum content.The compressive strength of the soluble magnesium alloy with lanthanum elements addition could reach 390 MPa and the material broke when the deformation reached 20.5%.The effects of the solid solution time on the microstructure and properties of soluble magnesium alloy were studied after heat treatment.After solution treatment,?phase(Mg₁₇Al₁₂ phase)was decomposed,and a large number of Al atoms were dissolved into the matrix,thereafter the grain boundary became more distinguishable,and the fine Mg-Al phase was precipitated out eventually.The solid solution treatment can decrease the dissolution of the soluble magnesium alloy gradually with the increase of the solid solution treatment time,and the solid solution treatment can improve the quasi-static compressive properties of the soluble magnesium alloy,and the quasi-static compressive properties of the soluble magnesium alloy increase with the increase of the solid solution treatment time.The compression fracture of the soluble magnesium alloy belongs to the brittle fracture of cleavage fracture.After the aging treatment of soluble magnesium alloy,the effects of the aging treatment on the microstructure and properties of the soluble magnesium alloy were studied.The results show that with the increase of the time of the aging treatment.The aging treatment can increase the dissolution of the soluble magnesium alloy gradually and with the increase of the aging treatment time,and the crystallite size increased accordingly.The quasi-static compressive properties of the soluble magnesium alloy increase with the increase of the aging treatment time.After heat treatment,the solubility of the soluble magnesium alloy was significantly different from that of as-cast soluble magnesium alloy.It can be found that the solubility of the soluble magnesium alloy mainly depended on the quantity and morphology of the?phase(Mg₁₇Al₁₂),the concentration of KCl solution,temperature.The quantity and morphology of the?phase(Mg₁₇Al₁₂)depended on the content of aluminum elements content and the rare earth elements.The solubility and the quasi-static compressive properties of the soluble magnesium alloy increase with the increase of the number of Mg₁₇Al₁₂,the plasticity of soluble magnesium alloy was reduced with increased Mg₁₇Al₁₂.