REPETITIVE-BLOW AND SINGLE-BLOW IMPACT TESTING OF WEAR-RESISTANT ALLOYS

Repetitive-impact and impact toughness tests provide two distinct meas ures of a material's ability to resist impact-related wear phenomena. These tests are described in detail and results are presented for a va riety of cast and forged wear-resistant alloys. In particular, past re search at the U.S. Bureau of Mines using the ball-on-block and bah-on- ball repetitive-impact test is reviewed and the wear-related phenomena associated with repetitive impact are described. Impact toughness was measured using a modified dynamic tear test. To account for the heter ogeneous and brittle nature of many wear-resistant alloys, a new tear test specimen was developed. Impact energies are presented for a varie ty of cast alloys and compared against literature values for static an d dynamic fracture toughness of similar alloys. It is shown that repet itive-impact and single-blow impact tests allow a unique characterizat ion of the material's behavior to crack initiation and propagation tha t dominate many wear environments.