微觀組織及力學(xué)性能的影響
(1. 上海交通大學(xué) 材料科學(xué)與工程學(xué)院，上海 200240；
2. 上海交通大學(xué) 輕合金精密成型國(guó)家工程研究中心，上海 200240；
3. 上海交通大學(xué) 金屬基復(fù)合材料國(guó)家重點(diǎn)實(shí)驗(yàn)室，上海 200240)
摘 要: 通過(guò)光學(xué)顯微鏡(OM)、掃描電鏡(SEM)、背散射電子衍射(EBSD)和力學(xué)性能檢測(cè)，研究不同Zn含量(0.5%、1.5%和2.0%(質(zhì)量分?jǐn)?shù)))的Mg-Zn-Ce-Zr合金在溫度為350 ℃，擠壓比為9，擠壓速率為10 mm/s條件下擠壓后的微觀組織和力學(xué)性能。結(jié)果表明：隨著Zn含量的增加，鑄態(tài)下晶間析出相明顯增多；擠壓后，Zn含量對(duì)合金晶粒度的影響不大，但棒材的絲織構(gòu)隨Zn含量增加而增強(qiáng)。由于第二相粒子的強(qiáng)化作用，隨Zn含量增加，合金的拉伸屈服強(qiáng)度從158 MPa增加到192 MPa，而抗拉強(qiáng)度從219 MPa提高到246 MPa。由于絲織構(gòu)強(qiáng)度增加，合金塑性隨Zn含量增加從33%降低至18%，添加0.5%Zn合金的伸長(zhǎng)率和拉壓對(duì)稱性最好。
關(guān)鍵字: Mg-Zn-Ce-Zr合金；織構(gòu)；微觀組織；力學(xué)性能；背散射電子衍射(EBSD)
properties of as-extruded Mg-Zn-Ce-Zr alloys
（1. School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University,
Shanghai 200240, China;
3. State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:The microstructures and mechanical properties of Mg-Zn-Ce-Zr alloys with different Zn contents (0.5%, 1.5%, 2.0% (mass fraction)) were investigated. These alloys were extruded with an extrusion ratio (λ) of 9 at temperature of 350 ℃ and run speed of 10 mm/s. The microstructures were observed by optical microscope (OM), scan electron microscope (SEM) and electron back scan diffraction (EBSD). The mechanical properties were tested by tensile test and compressive test at room temperature. The results show that more particles appear in the alloy with the increase of Zn content, and after extrusion, there are similar grain sizes in three alloys, and the intensity of ring basal textures increases with Zn content increasing. The tensile yield strength (TYS) increases from 158 to 192 MPa and the ultimate tensile strength (UTS) is enhanced from 219 MPa to 246 MPa with Zn addition increasing due to the second phase particles strengthening. However, the elongation decreases from 33% to 18% with Zn content increasing due to the variation of texture. The alloy with 0.5% Zn has highest ductility and lowest yield asymmetry in mechanical property.
Key words: Mg-Zn-Ce-Zr alloy; texture; microstructures; mechanical properties; electron back scan diffraction (EBSD)
