Find in Library

This work studied the relationship between biodegradation rate and grain size itself, excluding other structural factors such as segregations, impure inclusions, second phase particles, sub-structures, internal stresses and textures caused by alloying additions and deformation processing for pure Mg. A spectrum of grain size was obtained by annealing through changing the annealing temperature. Grain boundary influenced the hardness and the biodegradation behavior. The hardness was grain size-dependent, following a typical Hall–Petch relation: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>HV</mi><mo>=</mo><mn>18.45</mn><mo>+</mo><mn>92.31</mn><msup><mi>d</mi><mo>−</mo></msup><msup><mrow></mrow><mrow><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></msup></mrow></semantics></math></inline-formula>. The biodegradation rate decreased with decreasing grain size, following a similar Hall–Petch relation: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mi mathvariant="normal">i</mi></msub><mo>=</mo><mn>0.17</mn><mo>−</mo><mn>0.68</mn><msup><mi>d</mi><mo>−</mo></msup><msup><mrow></mrow><mrow><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></msup></mrow></semantics></math></inline-formula> or <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mi mathvariant="normal">w</mi></msub><mo>=</mo><mn>1.34</mn><mo>−</mo><mn>6.17</mn><msup><mi>d</mi><mo>−</mo></msup><msup><mrow></mrow><mrow><mfrac><mn>1</mn><mn>2</mn></mfrac></mrow></msup></mrow></semantics></math></inline-formula>. This work should be helpful for better controlling biodegradation performance of biodegradable Mg alloys through varying their grain size.