铱片的显微组织与室温拉伸断裂机制研究

Investigation on Microstructure and Fracture Mechanism of Iridium Sheet at Room Temperature

采用辉光放电质谱法(GDMS)、光学显微镜(OM)、扫描电镜(SEM)和力学试验机等测试手段,对不同加工状态的铱片杂质元素含量、金相组织、断口形貌和室温力学性能进行了研究。结果表明:加工状态对铱片的力学性能有重要影响,1 mm厚的热轧态铱片平均抗拉强度为213.6 MPa,延伸率为2.52%,主要为脆性沿晶断裂,部分为脆性穿晶解理断裂;而0.1 mm厚的冷加工态铱片平均抗拉强度为954.1 MPa,延伸率为0.55%,断裂模式主要为脆性穿晶断裂;两者在断裂之前均未发生明显的塑性变形,表现为脆性断裂模式。

Impurity contents, microstmctures, fracture surfaces and mechanical properties of iridium （Ir） sheets under different processing conditions were investigated by means of glow discharge mass spectrometry （GDMS）, optical microscope （OM）, scanning electron microscope （SEM） and tensile testing machine. The results indicate that processing condition has great effect on mechanical properties of Ir sheet. The ultimate tensile strength and elongations of 1ram hot rolled Ir sheet were 213.6 MPa and 2.52%, respectively, with a mixture fracture mode of brittle intergranular fracture and brittle transgranular cleavage fracture. The ultimate tensile strength and elongations of 0.1 mm cold worked Ir sheet were 954.1 MPa and 0.55%, respectively, with mainly transgranular brittle fracture. No obviously evidence of plastic deformation was occurred before tensile failure.