热处理温度对快速凝固Co_(47)Zr_(47)Ti_(6)合金微观组织及力学性能的影响

Effect of heat treatment temperature on microstructure and mechanical properties of rapidly solidified Co_(47)Zr_(47)Ti_(6)alloy

采用X射线衍射仪、光学显微镜、扫描电镜、透射电镜和电子万能试验机等研究了不同温度热处理后快速凝固B2型Co_(47)Zr_(47)Ti_(6)合金的微观组织及力学性能。结果表明:铸态和热处理态Co_(47)Zr_(47)Ti_(6)合金的微观组织均由大量B2-ZrCo相和少量Zr_(2)Co相组成。在3个热处理温度下,合金的相结构并未发生改变。823 K热处理后合金具有较大的屈服强度(888 MPa),而873 K热处理后合金具有最小的屈服强度(733 MPa)。873 K热处理后合金的弹性模量(17.3 GPa)位于人骨的弹性模量范围内(10~30 GPa),表明该合金是一种具有发展潜力的生物医用合金。对于823 K和873 K热处理后的合金,大量裂纹的形成及扩展或韧窝的形成均能吸收大量的塑性变形功,从而使得这两种热处理合金具有较高的塑性变形。

Microstructure and mechanical properties of rapidly solidified B2-type Co_(47)Zr_(47)Ti_(6)alloy after heat treatment at different temperatures were studied by mean of X-ray diffractometer,optical microscope,scanning electron microscopy,transmission electron microscopy and electronic universal testing machine.The results show that the microstructure of as cast and heat treated Co_(47)Zr_(47)Ti_(6)alloy is composed of a large amount of B2-ZrCo phase and a small amount of Zr_(2)Co phase.The phase structure of the alloy does not change at three heat treatment temperatures.The alloy after heat treatment at 823 K has a large yield strength(888 MPa),while the alloy after heat treatment at 873 K has a minimum yield strength(733 MPa).The elastic modulus(17.3 GPa)of the alloy after heat treatment at 873 K is in the range of elastic modulus of human bone(10-30 GPa),indicating that the alloy is a biomedical alloy with development potential.For 823 K and 873 K heat-treated alloy,the formation and propagation of a large number of cracks or the formation of dimples can absorb a large amount of plastic deformation work,which makes the two heat-treated alloy have higher plastic deformation.