A quantitative metallographic assessment of the evolution of porosity during processing and creep in single crystal Ni-base super alloys

被引：35

作者：

Buck, H. ^{[1
]}

Wollgramm, P. ^{[1
]}

Parsa, A. B. ^{[1
]}

Eggeler, G. ^{[1
]}

机构：

[1] Ruhr Univ Bochum, Inst Mat, Bochum, Germany

来源：

MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK | 2015年 / 46卷 / 06期

关键词：

Single crystal Ni-base superalloy; casting; heat treatment; creep fracture; porosity; NICKEL-BASED SUPERALLOYS; HIGH-TEMPERATURE CREEP; LOW-STRESS CREEP; PHASE;

D O I：

10.1002/mawe.201500379

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The present work reviews previous research on the evolution of porosity. It presents new results from a detailed study on the evolution of porosity during casting, heat treatment and creep of a single crystal Ni-base superalloy subjected to uniaxial tensile creep at 1050 degrees C and 160 MPa in [001] and [110] directions. A quantitative metallographic study was performed on carefully polished metallographic cross sections, monitoring sampling fields of 4500 x 1000 mu m(2) using the back scatter contrast of an analytical scanning electron microscope; evolutions of pore sizes and pore form factors were analyzed and all important details which were previously revealed in a synchrotron study could be reproduced. In addition, it was observed that micro cracks form at larger cast pores. They interlink and thus initiate final rupture. The [110] tensile creep tests showed lower rupture strains than the [001] experiments. In agreement with earlier work, this can be rationalized on the basis of aligned porosity along primary dendrites.

引用

页码：577 / 590

页数：14

共 33 条

[1]

[Anonymous], TMS LETT

[2]

[Anonymous], 1970, Quantitative Stereology

[3]

Bouse G.K., 1989, SUPERALLOYS SUPERCOM

[4]

Buck H., 2015, THESIS RUHR U BOCHUM