(1. 昆明理工大學(xué) 材料科學(xué)與工程學(xué)院，昆明 650093；
2. 中國(guó)科學(xué)院 金屬研究所，沈陽(yáng) 110016)
摘 要: 采用單向拉伸實(shí)驗(yàn)研究溫?zé)釛l件下擠壓態(tài)AZ31鎂合金板材5個(gè)不同方向的力學(xué)性能、顯微組織、斷口形貌。結(jié)果表明：擠壓態(tài)鎂合金力學(xué)性能具有明顯的各向異性，170 ℃時(shí)，各向異性最明顯，隨著拉伸方向與擠壓方向所呈角度的增大，抗拉強(qiáng)度從217 MPa增大到271 MPa，屈服強(qiáng)度卻從174 MPa減小到71 MPa。鎂合金在溫?zé)釛l件下變形機(jī)制為 拉伸孿生、 壓縮孿生和{0001}基面áa？滑移；沿著不同角度拉伸時(shí)，變形機(jī)制有所不同。拉伸方向與擠壓方向的角度小于45°時(shí)，擠壓態(tài)鎂合金表現(xiàn)為微孔聚集型的韌性斷裂；且隨著角度的增大，表現(xiàn)為韌-脆混合斷裂，其中角度為67.5°時(shí)，鎂合金以解理方式斷裂。
關(guān)鍵字: 鎂合金；溫?zé)崂煨阅埽粚\生；斷裂機(jī)制；各向異性
（1. Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The tensile properties, microstructure, appearance of fracture in five different planar directions of extruded AZ31 magnesium alloy sheets at the warm-temperature were investigated by uniaxial compression test. The results indicate that the extruded magnesium alloy sheets show high anisotropy, and the most obvious anisotropic temperature is 170 ℃. With the increase of the angle between tensile direction and extrusion direction, the tensile strength increases from 217 MPa to 271 MPa, and the yield strength decreases from 174 MPa to 71 MPa. There are three deformation mechanisms of magnesium alloys at warm-temperature, which include extension twinning, compression twinning and base slip. The deformation mechanism is different at different stretching angles. When the angle between tensile direction and extrusion direction is less than 45°, the fracture mechanism of magnesium alloy is micropore aggregation fracture. With the increase of angle, it is the mixed fracture of toughness and brittleness, and the cleavage fracture occurs at the angle of 67.5°.
Key words: magnesium alloy; warm-temperature tensile property; twinning; fracture mechanism; anisotropy
